KV Sanghatan Science Study Material Class X

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K ENDR I Y A V I DY A LA Y A SA NGA TH A N
SILCH AR R EGION
STUDY MATERIAL
CLASS X
SCI ENCE
2014-2015

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KENDRIYA VIDYALAYA
SANGHATAN
STUDY MATERIAL
OF
CLASS – X
2014 – 2015

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INDEX
PART OF THE STUDY MATERIAL :-
A) CHEMISTRY
B) BIOLOGY
C) PHYSICS
 GIST OF THE LESSON:-
O KEY CONCEPTS
O IMPORTANT DEFINITIONS
O USEFUL DIAGRAMS
O QUESTIONS
O HOTS AND VALUE BASE
QUESTIONS.
O MIND MAPS.

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CLASS X - SCIENCE
Chief Patron Shri. AvinashDikshit
Commissioner
KVS New Delhi
Patron Shri. SomitShrivastav
Deputy Commissioner
KVS, SilcharRegion
Advisor Shri. R.SenthilKumar
AssistantCommissioner
KVS, Silchar Region
Subject Contributors Mr. MANIK SUTRADHAR
PGT(Chem)
K V ONGC SRIKONA
Mrs. JAL SMITH
PGT(Phy)
KV MASIMPUR

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Syllabus
Unit
No
Name
I ChemicalReactionand Equation
II Acids, bases and salts
III Metals and non-metals
IV Carbon and its compounds
V Periodic classificationof elements
VI Life Processes
VII Contrl& Coordination
VIII How Do Organisms Reproduce ?
IX Heredity And Evolution
X Light : Reflectionand Refraction
XI Human eye and colorful world
XII Electricity
XIII Magnetic effectofcurrent
XIV Sources OfEnergy
XV Our Enviroment
XVI Managementof natural resources

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1. ChemicalReactionand Equation
 Chemical reaction involves a change in the physical, chemical properties composition and physical
state of substance.
 Chemical equation → symbolic representation of reactants and products using their chemical
formula.
 Writing of chemical equation
Two types
1. Word Representation
Example: Magnesium + oxygen → Magnesium Oxide
2. Symbol Representation
Example: Mg +O₂ → MgO
 A Chemical Equation contains
 Reactants →written on left side
 Products → written on right side
 Arrow which separate the both
Mg +O₂ → MgO
↓ ↓
Reactants Products
 Symbols for physical state of reactants and products.
 Solid (s)
 Liquid (l)
 Gas (g)
 Aqueous Solution (aq)
 Gas Equation (↑)
 Precipitate formula (↓)
 Direction of reaction (→)
 Chemical Reaction →developed on Law of conservation of Mass → Means mass of
reactantsconsumed equal to the mass of the products formed
 Balanced chemical equation
Number of atom of Reactants = Number of atom of products
 Unbalanced chemical equation
Number of atom of reactant ≠ Number of atom of products
 The following steps are involved the Balancing chemical equation.
1. Determining the reactants and products in a reaction.
2. Counting the number of atoms of each on both sides.
3. Selecting the elements that occur for the least number of the times in the equation.
4. Changing the coefficient of the molecules of reactant or product as required.
Eg: Iron +Steam → Magnetic Oxide of Iron +Hydrogen
1. Fe +H₂O →Fe₃O₄ +H₂
 Element No. of atoms on L.H.S No. of atoms on R.H.S
Fe 1 3
H 2 2
O 1 4
Select elements with highest No. of atoms
 Fe +4 H₂O → Fe₃O₄ +H₂
Start balancing with different elements
 3Fe +4 H₂O → Fe₃O₄ +H₂
 3Fe +4 H₂O → Fe₃O₄ +4H₂

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Balancing equation
 3Fe +4 H₂O → Fe₃O₄ +4H₂
2. KClO₃ → KCl +O₂ (Unbalanced equation)
2KClO₃ → 2KCl +3O₂ (balanced equation)
 Types of Chemical Reaction
1. Combination Reaction: Two or more reactants combine to form a single product.
Example: C + O₂ → CO₂
CaO + H₂O → Ca(OH) ₂
2. Decomposition reaction: A substance splits into two or more substances it is further three types.
a. Thermal Decomposition: takes place by absorption of heat.
Example: CaCO₃ (s) → CaO (s) +CO₂ (g)
b. Electrolytic Decomposition: Take place when electric current is passedthrough the compound in
molten or aqueous solution.
Example: 2 H₂O → 2H₂ (g) + O₂ (g)
c. Photo decomposition: By absorption of light
Example: 2AgBr → 2Ag+ Br₂
3. Displacement Reaction: the reaction in which one element displaces another element in a
compound.
Example: Mg +CuCl₂→ MgCl₂ +Cu
4. Double Displacement Reaction: Exchange of ions between the reactants.
Example: MgO +CaS →MgS +CaO
5.Precipitation Reaction: Two clear solutions combine to form an insoluble salts.
6. Oxidation and Reduction:
Oxidation: Addition of oxygen or removal of hydrogen.
Reduction: Addition of hydrogen or removal of oxygen.
 Corrosion: Eating up of metals due to attack of atmosphere gases or the surface of metals is called
corrosion.
 Causes damage to car bodies, brides, railing etc.
 Corrosion of iron called rusting
 Protection:
 Oiling and Greasing the metal articles
 Paint
 Galvanization.
 Rancidity: Oxidation of fat and oil.
 Prevention:
 Using Antioxidants.
 Packing food in nitrogen gas.
HOTS
Q.1 What Chemical compounds is used in white wash of walls? What happens when we mix it with water?
What reaction takes place on the walls after thewhite wash?
Ans. Quicklime (CaO), is used for white wash of walls.
CaO + H₂O → Ca(OH) ₂
On wall Ca(OH) ₂ + CO₂ → CaCO₃ +H₂O

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Q.2When Lead Nitrate combines with Potassium Iodide a yellow precipitate forms
a) Name the precipitate
b) Show the Chemical Reaction?
c) Name the type of Reaction?
Ans. a) Lead Iodide.
b) Pb(NO₃)₂ (aq) + KI(aq) → PbI₂ (s) + KNO₃ (s)
Lead Nitrate Potassium Iodide Lead Iodide Potassium Nitrate
Q.3. Why a few drops of sulphuric acid are added into water before electrolysis?
Ans. Pure water is a poor conductor of electricity. A few drops of Sulphuric acid are added to make it a
good conductor of electricity.
Q.4 When Carbon dioxide is passed through lime water, first it turns milky and on further passing the gas
milkiness disappear explain why?
Ans.If excess of CO₂ gas is passed through lime water, the milikiness disappears andthe solution again
becomes clear this is due to the change of insoluble CaCO₃ in to soluble calcium hydrogen carbonate as
follows.
CaCO₃ +CO₂ + H₂O → Ca(HCO₃)₂
Q.5The gases H₂ and Cl₂ do not react with each other even if kept together for a long time however in the
presence of sunlight, they readily combine. What does actually happen?
Ans. We know that in a chemical reaction energy is needed to break the bonds that in the reacting
molecules so that they may combine to form the products in the present case, sunlight is the source of
energy in the form of photons. Theenergy made available helps in breaking the bonds present in the reactant
molecules and chemical reaction leading to the formation of HCl gas take place.
H₂ (g) + Cl₂ (g) → 2HCl (g)
Q.6Why do potato chips manufacturers fill the packets with nitrogen gas?
Ans.This is done in order to flush out any air or oxygen present in the packet. In their absence chips will not
get rancid.
Q.7 Based on the reaction given below arrange the metals involved in these reactions decreasing order of
reactivity and also write nature of reactions.
a. Zn + CuSO₄ → ZnSO₄ + Cu
b. Cu + 2AgNO₃ → Cu(NO₃)₂ +Ag
c. Zn + FeSO₄ → ZnSO₄ + Fe
d. Fe + CuSO₄ → FeSO₄ + Cu
Ans.a. Since Zn displaces Cu from CuSO₄, it is more reactive than Cu
b. Cu displaces Ag from Ag from AgNo₃, it is more reactive than Ag
c. Zn displaces Fe from FeSO₄, it is more reactive than Fe.
d. Fe displaces Fe from CuSO₄, it is more reactive than Cu
Decreasing order of Reactions Zn> Fe> Cu > Ag
All are Displacement Reactions.
Q.8 Solid calcium Oxide was taken in a container and water was added slowly to it
i. State two observation made in the experiment.
ii. Write the name of the chemical formula of the product.
Ansi.Water start boiling and hissing noise will be produced
ii. Calcium Hydroxide will be formed
CaO (s) + H₂O (aq) → Ca (OH)₂ (s) + Heat
Q.9 Name the substance Oxidized and Reduced in the Chemical Reaction
MnO₂ + 4HCl → MnCl₂ +Cl₂ +2H₂O

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Ans. HCl → Oxidised
MnO₂ → Reduced
Q.10 On what basic Reaction is black and white photography based?
Ans. Black and white photography is based on the decomposition of AgBr in the presence of sunlight to
produce Silver.
2AgBr (s) → 2Ag + Br₂
Long Answer Questions.
Q.1 How can a balanced equation be made more informative? Explain with example?
Ans. (i) Physical states of the substance can be indicated by using the symbol (s) form solid, (l) for liquid,
(g) for gas and (aq) for aqueous solution.
(ii) Gaseous product may be represented by an arrow upward (↑) and a Precipitate formed by an arrow
downward (↓).
(iii) Concentrations of the solutions can be indicated by writing the symbol ‘dil’ for dilute and ‘conc’
for concentrated solution.
(iv) Heat changes by indicating by writing ‘+Heat’ with the products for exothermic reaction and ‘+Heat
with the reactants for endothermic reactions.
(v) Conditions of temperature and pressure and the presence of catalyst can be Indicated on the arrow.
Eg: Zn (s) + dil. H₂SO₄(aq) → ZnSO₄ (aq) + H₂(g) ↑
Q.2 Explain the following with suitable example?
a. Exothermic Reaction b. Endothermic Reaction
Ans. a. Exothermic Reaction: Those reactions in which heat is evolved during the reaction are called
exothermic reaction.
Eg: C (s) + O₂ (g) → CO₂ (g) + Heat
b. Endothermic Reaction: Those reactions in which heat is absorbed during the reaction are called
endothermic reaction.
Eg: C (s) + H₂O (g) + Heat → CO (g) +H₂ (g)
Q.3 (a) Why is combustion reaction an oxidation reaction?
(b) How will you test whether the evolved in a reaction is hydrogen?
(c) Why does silver not evolve hydrogen gas on reacting with dilute sulphuricacid
Ans. (a) Combustion reaction is an oxidation reaction because it is always carried in the presence of air or
oxygen for example
CH₄ (g) +2O₂ (g) → CO₂ (g) +2H₂O (l)
(b) Bring a burning match stick close to the mouth of the tube from which hydrogen gas escapes. The
gas will immediately catch fire and this will be accompanied by pop sound.
(c) Silver is less reactive metal in the sense that it occupies a place below hydrogen in the reactivity series.
Therefore it does not evolve hydrogen gas on reacting with either dilute
sulphuric acid or dilute hydrochloric acid.
Q.4 Identify the type of reaction in the following?
(a) ZnCO₃ (s) + 2HCl (aq) → ZnCl₂(aq) +H₂CO₃ (aq)
(b) 2NaBr (aq) + Cl₂ (g) → 2NaCl (aq) + Br₂ (aq)
(c) 2CuO (s) → 2Cu (s) +O₂ (g)
(d) 2Na (s) + Cl₂ (g) → 2NaCl (s)
Ans. (a) Double Displacement Reaction
(b) Displacement Reaction
(c) Decomposition Reaction
(d) Combination Reaction

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Q.5 (a) Why can not a Chemical change be normally reserved?
(b) Why it is always essential to balance a chemical equation?
(c) Can rusting of iron take place in distilled water?
(d) How will you know whether a sample of cheese has become rancid or not?
Ans (a) In a chemical change the products are quite different from the reactants. Therefore, it cannot be
normally reversed.
(b) A chemical equation has to be balanced to meet the requirement of the law of conservation of
mass. According to the law, the total mass of reacting species taking part in the reaction is the same as that
of the products formed since there is a direct relationship between the mass of the different Species and
their number, it is always essential to balance a chemical equation.
(c) No, rusting of iron cannot take place in distilled water because it neither contains dissolved oxygen
nor carbon dioxide. Both are essential for the rusting of iron
(d) It gives bad smell and it taste also changes.
SHORT ANSWER QUESTIONS
Q.1 In the following reaction:
MnO2 + 4HCl→ MnCl2 +2H2O+Cl2
a) Name the substance oxidized.
b) Name the substance reduced.
Ans .a) HCl
b) MnO2
Q.2 Suggest two methods to prevent rancidity?
Ans. a) By adding antioxidant.
b) By flushing the food articles.
Q.3 Can we place silver nitrates solution in an iron vessel? Why or Why not?
Ans. No, we cannot .Because iron is more reactive than silver .The following displacement reaction takes
place:
Fe +2AgNO 3 → Fe(NO 3)2+2Ag
Q.4What is an oxidizing agent?
Ans .An oxidizing agent is a substance which gives oxygen or gains hydrogen, that is oxidises other and
itself reduced.
Q.5 Why Hydrogen Peroxide kept in colored bottles?
Ans. This is done to cut off light because it decomposes into water and oxygen in the presence of light.
Q.6 The substance oxidized in a redox reaction is called……………………… agent.
Ans. Reducing agent
Q.7 What do you mean by Rancidity?
Ans. The oxidation of oil and fats due to aerated oxygen is called rancidity.
Q.8 What “aq” stands for?

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Ans.Itsstand for aqueous solution.
Q.9 Name one metal which does not corroded?
Ans. Gold
Q.`10 Does hydrogen gas support combustion?
Ans .No, it does not support combustion .Because it is highly combustible in nature.

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2. Acids, bases and salts
 Acids are the substances which are sour in taste.
OR
The substance which release Hydrogen ions when dissolve in water. Example: HCl,H2SO4
 Bases are bitter in taste.
OR
Substance which gives hydroxide ionswhen dissolved in water. Example:NaOH, KOH.
 Acid-Base Indicators
These are of two types:
 Show change in color .Example: Litmus solution, methyl orange.
 Show change in odor. Example:Onion,vanilla essence.
Indicator Color in neutral solution Color in acidicsolution Color in basic solution
Litmus Purple red blue
Methyl orange Orange red Yellow
Phenolphthalein Colorless colorless Yellow
 Chemical properties of Acids:-
 Action with metals
Metal +acid → Metal salt +hydrogen gas
Example: Zn +H2SO4→ZnSO4+H2
 Action with metal oxides
Metal oxides+ Acid→ Salt+ water
Example: CaO + 2HCl →CaCl2+H2O
 Action with metal carbonates and hydrogen carbonates
Example: CaCO3+2HCl→CaCl2+H2O+CO2
2NaHCO3+ H2SO4→Na2SO4+H2O+CO2
 Chemical properties of bases
 Action with metals
Metal+ Bases→ Salts+ Hydrogen gas
Example: 2NaOH+Zn→Na2ZnO2+H2
 Action with Non-metal oxides
Bases+ Non-metal oxides →Salts + water
Example: NaOH+CO2→ Na2CO3+H 2O
 Neutralization Reaction
Acid+ base →Salt +water
 Acid and base give ions (H+ by Acid) and (OH_ by Base) in their aqueous solution. Hence they have
tendency to conduct electric current.
 pH scale:- used to check acidity and basicity.
It ranges from 1 to 14.
 For Neutral Solution pH=7
Acidic Solution pH<7
 Basic Solutions pH>7
 SALTS:- Combination of positive and negative charge .Example: NaCl,KNO3
 Common salts-NaCl
 Bleaching powder (calcium oxychloride)
CaOCl2+Cl2→CaOCl2+H2O
USES:

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In textile industry, laundry, paper industry.
 Baking soda (sodium hydrogen carbonate) (NaHCO3)
NaCl+H2O+ NH3 + CO2→NH4Cl+ NaHCO3
USES:
As antacid, as fire extinguisher,additives in food and drinks
 Washing Soda(sodium carbonatedecahydrate) (Na2CO3.10H2O)
USES:
In laundry, removing hardness, manufacture of soap, paper etc.
 PLASTER OF PARIS (CaSO4.1/2H2O)
Chemical Name: Calcium Sulphate Hemihydrates
Preparation- CaSO4.2H2O --heat→CaSO4.1/2H2O+ 3/2 H2O
USES:
Setting fractured bones, in making toys, in making surface smooth.
HOTS
Q.1 Why we should not keep curd in cooper or brass vessel .What treatment should be given to these
vessels before use.
Ans .Curd is acidic in nature .it reacts with Cu & brass to form toxic compound and make food toxic for
consumption .so for protection these vessels have to be coated with a thin layer.
Q.2 Glucose, alcohol contains hydrogen yet their solutions do not turn blue litmus red. Why.
Ans. They do not produce H+ ion in solution.
Q.3 Name two metals which react with sodium hydroxide solution to produce hydrogen gas .give the
reaction.
Ans .Zinc and Aluminum
2NaOH+2Al→2NaAlO2+3H2
2NaOH+Zn→Na2ZnO2+H2
Q.4 Rain water and tap water conduct electricity but distilled water does not .Explain why.
Ans. Distilled water does not contain any acid, base or salt. Whereas tap or rain contain gases of air like
CO2,SO2,and NO2etc. When dissolve in water form acid .ex.CO2+H20→H2CO3
Q.5. Which is more acidic &why.
a)A solution with pH value of 6.0.
b) A solution with pH 5.0
Ans.[ H+] in solution with pH= 5.0 is 10-5M.
[H+] in solution with pH = 6.0 is 10-6M.
As 10-5>10-6, hence solution with pH = 5 is more acidic than the solution with pH = 6.0.
Q.6 How is Plaster of Paris is prepared .What reaction take place when it sets to hard.

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Ans .Plaster of Paris is prepared by heating Gypsum to a temperature of 1000C.
CaSO4.2H2O --heat→CaSO4.1/2H2O + 3/2H2O
On mixing with water, it reactsand become a hard mass due to formation of Gypsum again .the reverse
reaction take place.
Q.7What is difference between a base and a alkali .explain with suitable example.
Ans. Base is the substance which reacts with acid to form salt and water. These are metallic oxide or
hydroxide including NH4OH. Example: CaO, MgO, and NaOH etc.
The bases which is soluble in water and give OH- ions, called alkali .Thus CuO is a base but not an alkali.
Q.8 What is Acid rain? What is its pH? How does it affect the aquatic life?
Ans. When it rains, gases like CO2,SO2,etc. of the atmosphere dissolve into it &hence its pH<7 .When pH
of rain below 5.6 ,it is called acid rain .When this acid rain flow into the river,the pH of river water falls
and the survival of aquatic life become difficult.
LONG ANSWER QUESTION
Q.1 Explain the importance of pH in daily life.
Ans. a) In humans and plants.-In human body the reaction occur at pH ranges from 7.0 to 7.8 .if it falls then
survival is difficult.
Plants have a healthy growth only when the soil has a specific pH range which should be neither
alkaline nor highly acidic.
b)In digestive system – HCl in stomach help in digestion of food. It help to kills the bacteria that may enter
into the stomach along with the food.
c)Tooth Decay caused by acids – Acid is produced in the mouth by degradation of sugar .saliva produced in
the mouth is alkaline help to neutralize the acids.
d) Self defense of animals and plants through chemical welfare.
Q.2Solutions A, B, C,D have pH values 3,4,5,6 respectively. Arrange them in increasing order of acidic
characteristic .giving reason.
Ans. D<C<B<A
Increasing order
H+ ion conc. of A, B,C,D are 10-3,10-4,10-5,10-6 respectively. As higher the [H+] more acidic is the
solution.
Q.3Why tartaric acid added into baking soda to get baking powder.
Ans. Tartaric acid is added to neutralize the sodium carbonate formed on heating if it is not added; the cake
would taste bitter due to presence of sodium Carbonate.
Q.4. (a) How is bleaching powder prepared. (b) What happens if bleaching powder is exposed to air for a
long time. (c) Giveitsuses.
Ans. a) Ca (OH)2+Cl2→CaOCl2+H2O

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b) CaOCl2+CO2→CaCO3+Cl2
c) USES
In paper industry, textile industry, laundry.
Q.5. what is the difference between:
a) Strong acid and weak acid.
b) Strong base and weak base
Ans .Acids like HCl,H2SO4 which dissociate completely in the aqueous solution to produce H+ ions called
strong acids .Acids like CH3COOH,H2CO3 which dissociate only partially in the aqueous solution to
produce a small amount of H+ ion, called weak acid.
Bases like NaOH, KOH etc. which dissociate completely in the aqueous solution to produce a large amount
of OH- ions, called strong base .While NH4OH,Ca(OH)2 etc. which dissociate only partially in the aqueous
solution called weak base.
SHORT ANSWERS QUESTION
Q.1 Classify the following as strong and weak acids.
a) HCl b) H2SO4 c) H3PO4 d) HNO3 e) CH3COOH
Ans. Strong acid: - HCl, H2SO4, HNO3
Weak acid: H3PO4, CH3COOH
Q.2Aceic acid is highly soluble in water but is still a weak acid .Why.
Ans. The strength of an acid is not related to its solubility in water .but depend on extent of dissociation
.Itdissociates less so weak acid.
Q.3Where is Hydrogen used as fuel.
Ans.As a Rocket Fuel.
Q.4 Define pH.
Ans. It is the magnitude of the negative power to which 10 must be raised to express the Hydrogen ion
conc. of the solution in moles per liter.
Q.5A doctor applied surgical bandage in the fractured bones of a patient after making them wet. What
changes are likely to occur?
Ans. Surgical bandage is made up of plaster of Paris .When applied on the fractured bones after making
them wet, it changes into hard mass called Gypsum.
CaSO4.1/2H2O+3/2H2O→ CaSO4.2H2O.The hard mass keeps the bone in the proper position.

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3. Metals and non-metals
 Elements are classified broadly into two categories on the basis of properties:
 Metals: Iron, Zinc, Copper, Aluminium etc.
 Non- metals: Chlorine, Nitrogen, Hydrogen, Oxygen, Sulphur etc.
 Apart from metals and non-metals some elements show properties of both metals and non-metals,
Example: Silicon, Arsenic, Germanium.They are called metalloids.
Comparison of physical and chemical properties of metals and non – metals:-
Sl.
No.
Property Metals Non-Metals
1 Physical State Metals are solid at room
temperature. Except mercury
and gallium.
Non-metals generally exist as
solids and gases, except Bromine.
2 Melting and boiling
points
Metals generally have high
m.pt and b.pt except gallium
and caesium.
Non-metals have low m.pt and b.pt
except diamond and graphite.
3 Density Generally high. Generally low.
4 Malleability and
Ductility
Malleable and ductile. Neither malleable nor ductile.
5 Electrical and
thermal conductivity
Good conductors of heat and
electricity.
Generally poor conductors of heat
and electricity except graphite.
6 Luster Poses shining lustre. Do not have lustre except iodine.
7 Sonorous sound Give sonorous sound when
struck.
Does not give sonorous sound.
8 Hardness Generally hard except Na, K Solid non-metals are generally soft
except diamond.
Comparison of Chemical Properties of Metals and Non-metals:-
1 Reaction with
Oxygen
Metal + Oxygen Metal oxide
4Na(s) + O2(g)  2Na2O(s)
4Al(s) + 3O2(g)  2Al2O3
Metals form basic oxides. Zn
and Al form amphoteric oxides (they
show the properties of both acidic
and basic oxides)
Most of the metal oxides are
insoluble in water. Some of them
dissolve to form Alkali
Na2O(s) + H2O(l)  2NaOH(aq)
Non-metal + Oxygen  Non-metal
oxide C +
O2 CO2
S + O2 SO2
Non-metals form acidic oxides.
CO and H2O are neutral oxides(they
are neither acidic nor basic in nature).
Non-metal oxides are soluble in water
They dissolve in water to form acid.
example SO2 +H2O  H2SO3
2 Reaction with
water
Metals react with water to form metal
oxides or metal hydroxide and H2 gas
is released. 2Na(s) +
2H2O(l)  2NaOH +
H2(g) + heat
Non-metals do not react with water,
steam to evolve hydrogen gas. Because
Non-metals cannot give electrons to
hydrogen in water so that it can be
released as H2 gas.
3 Reaction with
dilute Acids
Metal + Acid  Metal salt +
Hydrogen
Mg(s)+2HCl(aq)MgCl2(aq)+H2(g)
2Na(s)+H2SO4Na2SO4(aq)
Non-metals do not react with acids to
release H2 gas Reason-
Non-metals cannot loose electrons and
give it to Hydrogen ions of acids so
that the gas is released.

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+H2(g)Metal+HNO3H2 gas is not
displaced.
Reason- HNO3 is strong oxidizing
agent. It oxidises hydrogen to water.
4 Reaction with
salt solutions
When metals react with salt solution,
more reactive metal will displace a
less reactive metal from its salt
solution.
CuSO4(aq)+Zn(s)ZnSO4(aq)+Cu(s)
When non-metals react with salt
solution, more reactive non-metal will
displace a less reactive non-metal from
its salt solution.
2NaBr(aq)+Cl2(g)2NaCl(aq)+Br2(aq)
5 Reaction with
Chlorine
Metal + Chlorine  Metal Chloride
ionic bond is formed. Therefore Ionic
compound is obtained.
2Na + Cl2 2NaCl
Non-metal + Chlorine  Non-metal
Chloride.
Covalent bond is formed. Therefore
covalent compound is obtained.
H2(g) + Cl2 2HCl
6 Reaction with
Hydrogen
Metals react with hydrogen to form
metal hydride.
This reaction takes place only for
most reactive metals.
2Na(s) + H2(g)  2NaH(s)
Non-metals react with hydrogen to
form hydrides
H2(g) + S(l)  H2S(g)
Properties of ionic compounds
1. Physical nature:solid and hard due to strong force of attraction. (generally brittle)
2. Melting point and boiling point:have high M.P and B.P, as large amount of heat energy is required
to break strong ionic attraction.
3. Solubility: soluble in water and insoluble in kerosene and pertrol.
4. Conduction of electricity:ionic compounds in solid state-----does not conduct electricity.
Reason—Ions can not move due to rigid solid structure. Ionic compounds conduct electricity in
molten state.
Reason-- Ions can move freely since the electrostatic forces of attraction between the oppositely
charged ions are overcome due to heat.
Occurrence of metals.
It occurs in Earths crust, sea-water
Elements or compounds, occuring naturally Minerals that contain very high
percentage
in the earth’s crust of a perticular metal and these metals can be
extracted economically on a large scale.
e.g Bouxite ore → Aluminium
Haematite → Iron
OresMinerals

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Q.1 GIVE REASONS:
a) Platinum, gold, and silver are used to make jeweler
b )Sodium ,potassium and lithium are stored under oil.
c) Aluminum is a highly reactive metal; still it is used to make utensils for cooking.
Ans. Platinum, gold, and silver are highly unreactive metals .Therefore; they do not undergo corrosion due
to attack by moisture and atmospheric gases. Further, they are highly malleable and ductile. Because of
these properties, i.e, resistance to corrosion, high malleable and ductile, these are used to make jewelers.
b) Because they are readily attacked by O2 present in air to form their respective oxides .they also react with
moisture present in air producing H2 gas which sometimes catches fire and causes accidents .so to protect
from such accident they are in oil.
c) When exposed to then moist air a layer of Aluminum oxide is formed .now with this formation it
become resistance to corrosion and used to make utensils.
Q.2 What are amphoteric oxides .give examples of two amphoteric oxides.
Ans, Oxides which react with both acids and bases to form salts and water are called amphoteric oxides.
Two examples are:-Zinc Oxide and Aluminum Oxide.
Q.3 Which metals are called strategic metals. Give a few examples of the uses to which they are put.
Ans. Metals like titanium, chromium, zirconium etc. which are used in the country defense are strategic
metals. These metals and their alloys are used in the atomic energy, jet engine and in making high grade
steel.
Q.4 What is Anodizing. For what purpose is it done?
Ans. Anodizing is a process of coating a thick layer of aluminum layer on the surface of aluminum articles
.It protect the the aluminum from corrosion.
Q.5 ‘E’ is an element which is one amongst Copper, Zinc,and Aluminum and Iron,it show following
properties:
a) One of its ore is rich in E2O3
b) E2O3is not attacked by water.
c) It forms two chlorides ECl2 and ECl3. Name the element and justify your answer.
Ans. As it form two chlorides it mean element has variable valency of 2 &3 .Out of the element listed iron
exists in divalent and trivalent forms.
a) The ore rich in Fe2O3is Hematite.
b) Hematite is not attacked by water.
c) The two chlorides are FeCl2 and FeCl3.
Q.6 An element reacts with oxygen to form an oxide which dissolves in dil. Hydrochloric acid. The oxide
formed also turn a solution of red litmus blue. Is the element a metal or non-metal? Explain with the help of
example.
Ans. The oxide of the element is basic as it turns red litmus blue .This means that the element is a metal
(M).Let the metal be sodium (Na).The chemical equation that are involved are:

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4Na + O2→ 2Na2O
Na2O +H2O→ 2NaOH
Na 2O+ 2HCl →2NaCl +H 2O
Q.7 Give reason for the following;
a) Zinc can displace copper from copper sulphate solution.
b) Silver articles become black sometime when exposed to air.
c)A metal sulphide is converted to its oxides to extract the metal from sulphide ore.
Ans .a): Zinc is placed above copper in the activity series. It is more reactive than Cu. Therefore; it can
easily displace copper from copper sulphate solution.
Zn +CuSO4 →ZnSO4 +Cu
b)Air contain traces of hydrogen sulphide gas. Sulphide has a tendency to combine with H2S to form silver
sulphide which is black in color .On account of this, silver article become black.
c) Metal sulphide is normally converted into oxide by heating with excess of air .This process is called
roasting. Actually, the oxide of metal which is formed can be easily reduced to the metallic form by
reduction with carbon or some electropositive element.
Q.8 a)Distinguish between roasting and calcinations .
Ans.
CALCINATION ROASTING
It is carried out in absence of air or oxygen. It is carried out in presence of excess of air.
Metal carbonate→ Metal Oxide + CO2 Metal Oxide+ Carbon→ Metal + CO2
Q.9 a) Are all pure liquid bad conductor of electricity.
b) Name a liquid which is a good conductor of electricity but does not electrolysis on passing electric
current.
c) If pure water is used, no electrolysis takes place. Why
d)Name one practical application based on the phenomenon of electrolysis.
Ans. a) NO, there is exception also. Mercury in pure state is a good conductor of electricity.
b)Mercury .but does not undergo Electrolysis.
c) Pure water does not dissociate into ions on passing electric current.
d) The process of electroplating on the surface of metals is based on the phenomenon of electrolysis.
Q.10 What is the Activity series of metals.
Ans.The relative electron releasing tendency of some important metals are summed up in the activity series.
Q.11 Define the following.
a) Metal refining

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b)Alloy
c) Amalgam
d) Ore
ans. a) Metal Refining:-The conversion of crude metal into pure metal.
b) Alloy: - The homogenous mixture of more than one metal or even metal and non-metal.
c) Amalgam: -It is an alloy in which mercury is one of the components.
LONG ANSWER QUESTION
Q.1Corrosion of metal is not always harmful. Illustrate.
Ans. Corrosion is a very harmful process resulting in slow eating up of a metal. But corrosion of aluminum
is useful .A layer of aluminum oxide formed as a result of chemical reaction gets deposited on the surface
of metal .It forms a protective coating on the surface and prevents the attack of water ,air and acids.
Q.2 Why are positively charged ions called cations while negatively charged called anions.
Ans. When electric current is passed through the molten or aqueous solution of an electrolyte, the positively
charged ions migrate towards the negative electrode or cathode. They are therefore, called cations. The
negatively charged ions migrate towards the positive electrode or anode. They are therefore, called anion.
Q.3 Explain, why solid sodium chloride does not conduct electricity but in the molten state or in the
aqueous solution, it is a good conductor of electricity.
Ans .In solid state the movement of ions is not possible due to strong inter-ionic attraction while in molten
state the ion of sodium chloride are free to move and conduct electricity.
Q.4 Why do atoms combine.
Ans. Atoms combine to form compounds so as to acquire the stable electronic configuration of the nearest
noble gas, for example,the electronic configuration of Na is 2,8,1 and Cl is 2,8,7 .The Na has one electron
more than neon gas configuration and Cl has one electron less than argon gas configuration so in order to
get noble gas configuration Na loses one electron and Cl accept the electron.
Q.5 Why is sodium chloride soluble in water but not in kerosene or oil.
Ans. Water ispolar in nature so NaCl dissociate in their ions and dissolve, while kerosene is a non- polar
solvent so NaCl doesn’t dissociate and dissolve.
Q.6a) Why metals conducts electricity.
b) Name three common compound forms in which metals occur in nature.
ans. a) Because the attraction of the nucleus on the valence electron is minimum. Hence, electron is free to
move.
b) Three common compound forms in which metal occur in nature are:
I. Oxides e.g., Bauxite (Al 2O 3.2H 2O)
II. Sulphides e.g., Iron Pyrites (FeS2)
III. Carbonates e.g., Calamine (ZnCO3)
Q.7 Oxides of the metals which are high in the activity series are not reduced by carbon. How will you
account for it?

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Ans .Metals which lie high in the activity series is reactive in nature the oxides of these metals are
extremely stable. Moreover, the metals present in these oxides are very strong reducing agents themselves
.They cannot loseoxygentocarbonwhich is a weaker reducing agent .As a result, these oxides cannot be
reduced to the metallic form by heating with carbon.
Q.1 Metals at the top of the activity series do not occur in the Free State. Explain.
Ans. Metals at the top of the activity series are highly reactive in nature and are very strong reducing agent
.They therefore, occur as oxides, sulphides and carbonates etc. and do not occur in the Free State.
Q.2What is the difference between the normal and Lewis symbol of an element.
Ans. in the normal symbol, the valence electrons are not shown while in the Lewis symbol, these are shown
either by dots or by crosses. For example, ordinary symbol of sodium is Na while its Lewis symbols Na..
Q.3What is a Thermite reaction.
Ans. It is the reduction of certain metal oxides such as MnO2, Cr2O3, Fe2O3etc by aluminum metal upon
strong heating .It is highly exothermic in nature. For example:
Fe 2O 3 +2Al →Al 2O3+2Fe +Heat
Q.4Name the alloy of
1. Aluminum
2. Lead
3. Copper
ans .1. Duralumin
2. Solder
3. Brass
Q.5Why is non-metals gases at room temperature.
Ans. In the molecular form, non-metals exist as a single molecules e.g., hydrogen, oxygen, nitrogen, carbon
dioxide etc. The attractive forces in these molecules are quits weak. Therefore exits as gases at room
temperature.
Q.6 Metals at the top of the activity series do not occur in the free state. Explain.
Ans .Metals at the top of the activity series are highly reactive in nature and are very strong reducing
agents. They therefore, occur as oxides, sulphides and carbonates etc .and do not occur in the free state.
Q.7 Name two neutral oxides.
Ans. Carbon monoxide and nitrous oxides
Q.8What is the chemical formula of rust.
Ans. Fe2O3.xH2O.
Q.9 Name the process used for the enrichment of the sulphide ore.
Ans. Froth Floatation Process.

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Q.10 Arrange the following in decreasing order of reactivity. Fe, Zn, Ca, Mg, Cu, Ag
Ans. Ca>Mg>Zn>Fe>Cu>Ag
Q.11 Name two metals which exits in the Free State.
Ans. Gold and Platinum
Q.12 which metal is the best conductor of electricity.
Ans. Silver
Q.13 Name two non- metal which exist in solid state and onenon-metals which exist in liquid state.
Ans. Solid state:-Sulphur and Phosphorus
Liquid state: -Bromine.
Q.14 Which metal is used in amalgams.
Ans. Mercury
Q.15 What is the name of the bond formed when a metal atom combines with the atom of non-metal.
Ans. Ionic and electrovalent bond.

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4. Carbon and its compounds
Important terms and conditions
 Versatility of carbon: Carbon is a non-metal and occurs in free as well combined state in nature.
 Free State: Diamond, graphite and coal.
 Combined state :
1.Solid state: All animals and plants products.
2.Liquid state: Petroleum and vegetable oil.
3.Gaseous state: In air has CO2.
 Catenation:
It combines with itself and forms a long chain.Carbon has 4 valance electrons carbon cannot form
an anion C-4 by gain of electrons. It can also not form of cations C+4 by loss of electron. It can share
its balanced electrons with other carbon atoms or atoms of non-metal and forms covalent bonding.
 Compounds of carbon: Simplest compounds of carbon are hydro carbon and simplest hydro carbon
is methane.
Classification of hydro carbon:
Saturated hydro carbon: Unsaturated hydro carbon:
Compounds having single bond compounds having double and triple bonds.
ALKANES ALKENES AND ALKYNES.
Alkanes (CnH2n+2) alkenes(CnH2n) alkynes. (CnH2n+2)
e.g ethane (C2H6) eg:Ehene C2H4Ethyne C2H2
Sr no Hydro carbons Definitions Examples
1 Straight chain All carbons are in form of
straight chain
Butane
2 Branched Chain One or more carbon atoms are
attached to main straight line
Isobutane.
3.
a
b
Ring or cycle
hydro carbon
Saturated
Unsaturated
Carbon atoms are in form of
ring and atoms bonded by single
covalent bond.
Carbon atoms are bonded by
one or more doubled covalent
bond.
Cyclohexane.
Benzene.
Isomerism: The phenomenon of existence of compounds in two or more forms with same molecular
formula but different structure.
Functional group: An atom or groups of atoms which makes a carbon compounds reactive and decide its
properties.

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Sr.no. Hetero
atoms
Functional
groups
Formula of
functional
group
example
1. Cl/Br Halo-
chloro/bromo
-Cl,-Br Chloromethane(CH3Cl)
2. oxygen 1.Alochol
2.Aldehyde
3.Ketone
4.Carboxylic
acid
-OH
-CHO
>C=O
-COOH
Ethanol
C2H5OH
Methanal
HCHO
Propanone
CH3COCH3
Ethanoic acid CH3COOH
HOMOLOGOUS SERIES:A series of compounds in which the same functional group substitute for
hydrogen in a carbon chain, such that successive compounds differ by CH2 groups e.g CH4,C2H6,C3H8 etc.
NOMENCLATURE OF CARBON COMPOUNDS:
Prefix word root+suffix+Functional group.
CARBON COMPOUNDS:
ETHANOL: C2H5OH common name is ethyl alcohol
ETHANOIC ACID: CH3COOH.Common name is acetic acid.
ESTERIFICATION REACTION:The reaction between carboxylic acid and an alcohol in the presence of
conc. Suphuric acid to form a sweet smelling substance ester. .e.g
CH3COOH+C2H5OH -----------→ CH3COOC2H5+H2O
Saponficationreaction : Alkaline hydrolysis of ester produces soaps.
CH3COOC2H5+NaOH ---heat→CH3COONa+C2H5OH
Reaction with carbonates and hydrogen carbonates: reaction of ethanoic acid with carbonates or bi
carbonate evolves carbon di oxide gas.
2CH3COOH+Na2CO3 2CH3COONa+CO2+H2O
SOAP AND DETERGENT: Soap is sodium and potassium salt of long chain of carboxylic acid. They
foam lather with soft water only. Detergent are ammonium or sulphonate salts of long chain carboxylic acid
.they even remain effective in hard water and foam lather.
HOTS
Conc H2SO4

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Q.1 Give reason for the following
(a). The element carbon forms a large no. of compounds
Ans. (a). Catenation: Carbon has the unique property of self-linking which is known catenation.
In fact, any number of carbon atoms can be linked to one another by covalent bonds. This is on account if
the stability of C-C bonds since the size of the carbon atom is quite small. Linking of carbon with
other atoms carbon is tetravalent in nature and can readily form bond with atoms like hydrogen, oxygen,
nitrogen, sulphur etc. by electron sharing.
Q.2 what are enzymes? Name the enzymes required for the fermentation of sugarcane to Ethanol?
Ans. Enzymes are the biocatalysts which catalyze the reactions in the living being. In the process of
fermentation of sugar into ethanol, two enzymes are used, they are invertase and zymase..
C₁₂H₂₂O₁₁ + H₂O → C₆H₁₂O₆ + C₆H₁₂O₆
C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂
Q.3 A to F are the structural formula of organic compounds?
A. H H B. H─C≡C─H C.H H D. H
│ │ / │
H─C ─ C─H C═C H─C≡C─C─H
│ │ / │
H HHHH
E. H F. H H
│ │ │
H─C─Br H─C─C─H
│ │ │
H HH
(i)Give the letters which represent the same family
(ii)Give the letters which do not represent hydrocarbons
(iii)How can C be converted into A
Ans. (i) Letter B and D represent the family of alkynes.
(ii) Letter E and F represent any hydrocarbon.
(iii)C can be converted in to A passing by hydrogen in the presence of Ni at 473K.
Q.4 (a) Why on some of compound called saturated and other unsaturated compounds?
(b) Which of these are more reactant?
(i) H H (ii) H HHH
│ │ │ │ │ │

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H─C─C─Br H─C─C─C─C─CC─H
│ │ │ │ │ │
H HHHHH
(c) Write the names of the compounds?
Ans. (a) The compounds in which only C─C single bond are present are called saturated Compounds these
are named because of their low reactivity. The compounds in which at least one (C═C) or (C≡C) is present
are called unsaturated compounds.
(b) Unsaturated compounds are more reactive than saturated compounds.
(c) a. Bromo ethane
b. Hex-1-yne
Q.5 Distinguish between esterification and saponification reactions of organic compounds.
Ans. In the esterification reaction an acid reacts with alcohol in the presence of conc. H₂SO₄ to
Form an ester with a pleasant or fruity smell.
CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O
Saponification is quite different from esterification because in this case an ester reacts with an alkali
to from salt of acid and alcohol.
CH₃COOC₂H₅ + NaOH → CH₃COONa + C₂H₅OH
Q.6 (a) What is homologous series of substances?
(b) In organic compound, from alkyl group and functional group which part determines the Physical and
chemical properties?
Ans. (a) A series of similarity constituted compounds in which the members present have the Same
functional group, same chemical properties and any two successive members in a particular series differ in
their molecular formula by CH₂ group.
(b) functional group determines the physical and chemical properties of compounds.
Q.7 How do diamond and graphite differ in their structure? Is there any effect of structures on The nature of
the these?
Ans. Diamond and graphite are the two crystalline allotropic forms of carbon but they differ in Their
structure. In diamond, all the four valance electrons of carbon atoms are involved in the covalent bond
formation with the electrons of neighboring C-atom.
In graphite only three electrons participate in the bond formation while the fourth Electron is free
diamond without any free electron in a poor conductor of electricity. While Graphite with free electron
available is a good conductor.
Q.8 Why are soaps are not so effective in case of hard water?
Ans. Soaps are the sodium or potassium sales of higher fatty acids. They reacts with Ca2+ and Mg2+ ions
by present in hard water and form corresponding calcium and magnesium salts of the acids since these salts
are insoluble in water, a lot of soap is water as curdy white precipitate also known as scum.

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Long Answer Question
Q.1 Write chemical equation if the reaction of Ethanoic acid with :
1. Sodium 2. Sodium carbonate
3. Ethanol in the presence of conc. H2SO4.
Ans. 1.2CH3COOH + 2Na → 2CH3COONa + H2
2. 2CH2COOH + Na2CO3 → 2CH3COONa + CO2 + H2O
3.CH3COOH + C2H5OH → CH3COOC2H5 + H2O.
Q.2 Write the structural formulas and IUPAC names of all the isomers of Hexane C6H14.
Ans.1 CH3─CH2─CH2─CH2─CH2─CH3
Hexane
2. CH3
│
CH3─CH─CH2─CH2─CH3
2-Methyl pentane
3. CH3
│
CH3─CH─2CH─CH2─CH3
2,3 Dimethyl butane
4. CH3 CH3
│ │
CH3-CH-CH2-CH3
2,2 Dimethyl butane
Q.3 Both carbon and Silicon belong to group 14 of the periodic table. But the tendency to exibhitcations in
the carbon is much more than in the silicon. Explain?
Ans. The size of carbon atom is small as compared to the of silicon. This is quite expected also as the
atomic size increases atom a group. Therefore C-C bond is smaller and stronger than Si-Si bond .As a
result, any of carbon atoms can be linked to each other resulting in a long number if carbon compounds.
However, this is not possible in silicon and only a few atoms can be linked by covalent bond.
Q.4 A compound ‘X’ has the molecular formula C3H6O with structural formula CH3CH2. Give its IUPAC
names can another compound have the same molecular formula? Give the structural and IUPAC names of
that compound also?
Ans. The IUPAC names of X is proposal another compound Y can also have the same molecular formula
but different structural formula.
It is O

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║
CH3-C-CH3 IUPAC Name Propanone
The compound X and Y are related to each other as functional Isomers
Q.5 Give one example each of the compound having the following functional groups. Also give their
Names?
(i) Aldehyde group (iv) Ester group
(ii)Alcoholic group (v) Keto group
(iii)Carboxyl group
Ans.
Functional Group Example IUPACName
CHO HCHO Methanal
OH CH3OH Methanol
COOH HCOOH Methanoic acid
COOR CH3COOCH3 Methyl ethanoate
Q.6 What is meant by denatured alcohol? What is the need to denature alcohol?
Ans. Ethanol which has been made unfit for drinking purposes by adding poisonous substances like
Methanol, pyridine etc.
Need: To supply cheaper alcohol to industries and to refrain people from drinking, alcohol is Denatured by
adding poisonous substance such as methanol, pyridine etc.
Q.7. What is substitution reaction? Illustrate with example?
Ans.A reaction in which one or more hydrogen atoms of an organic compound is/are replaced by other.
Atom or group without any change in the react of the molecule is called substitution reaction.
CH4 + Cl → CH3Cl + HCl
Q.8 Write the molecular formula of
(i) an alkane (ii) an alkene (iii) an alkyne containing six carbon atoms
Ans. (i) Alkane: Put n=6 is the general formula CnH2n+2, we have C6H14
(ii) Alkene: Put n=6 is the general formula CnH2n, we have C6H12
(iii)Alkyne: Put n=6 in the general formula CnH2n-2, we have C6H10
Q.9 Give an example of each of the following
(a) A carbon containing two double bonds
(b) A molecule in which central atom is linked to three other atoms

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(c) An organic compound which a soluble in water.
Ans. (a) Carbon dioxide :Ӧ ═ C ═ Ӧ:
(b) Ammonia H─̈N─H
│
H
(c) CH3CH2OH
Q.10 (a) Name the B fatty acids whose sodium or potassium salts are present in soaps?
(b) What is scum? How is it formed?
(c) Label the hydrophilic and hydrophobic part in the following?
Ans. (a) Palm tic acid, stearic acid, and oleic acid
(b) The Ca2+ and Mg2+ ions present in hard water react with soap to form white precipitate. The White
precipitate called sucm.
2C17H35CoNa + Ca2+→ (C17H35Co)2Ca + 2Na+
(c) CH3(CH2)10CH2 ─ OSO3
-Na+
Hydrophobic part Hydrophilic part
CH3(CH2)14CH2 ─ N+(CH3)3Br-
Hydrophobic part Hydrophilic part
Q.1 Why is carbon is tetravalent?
Ans .Carbon atom has 4 e- in the outermost shell. It needs 4 more e- to complete its octet Therefore, carbon
is tetravalent.
Q.2 Name a cyclic unsaturated hydrocarbon?
Ans. Benzene
Q.3 what is Petrol?
Ans. Petrol is a mixture of saturated hydrocarbon containing 7-10 C- atoms.
Q.4 what is rectified spirit?
Ans. The alcohol obtained by distillation of the mixture obtained after fermentation of molasses or sweet
fruits are called rectified spirit. It contains about 95% alcohol and 5% water.
Q.5 Name the catalyst commonly used in hydrogenation of oils to form fats?
Ans. Nickel
Q.6 what is scum?
Ans. The Ca and Mg salt of soap.

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Q.7 Name the hydrophobic and hydrophilic end of soap?
Ans. The long hydrocarbon chain which is insoluble in water is the hydrophobic end while –COO- end
which dissolve in water is the hydrophilic end.
Q.8 Why is candle flame generally yellow?
Ans. It is due to presence of sunburn carbon particles. When light fall on them, they scatter yellow color.
Q.9 An unknown compound has the smell of vinegar .Identify it.
Ans.The compound is acetic acid.
Q.10 Why is high temperature not favorable for alcoholic fermentation?
Ans. The high temperature destroys the enzymes which are needed to carry fermentation.

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5.Periodic classification of elements
Classification of elements: the arrangement of element in such manner that element with similar properties
are grouped together while elements with dissimilar properties are separated.
Early attempt to classify elements:
DOBEREINER’S TRIADS:
He arranged the elements with similar properties in a group of three known as triad in such a manner
that the atomic mass of the middle element was approximately the average of the other two elements
LIMITATIONS:
Only three triads were identified from the element known at that time .hence this classification was not
useful.
NEWLAND’S LAW OF OCTAVES:
He arranged the element in the order of increasing atomic masses starting with hydrogen(least atomic
mass) and ended with thorium having atomic mass 56 . According to him, the properties of every
eighth element are similar to the firstelement. It was compared to music notation sa,re ,ga ,ma, pa ,dha
,ni ,sa,and thus the name Newlands law of octaves(notes of music ).
LIMITATIONS:
1. It was applicable only for lighter element having atomic mass upto 40 amu.i.e.upto calcium .
2. He believed that only 56 elements existed in nature but later on more elements were discovered
whose properties did not fit into Newland law of octaves.
3. Some elements having different properties were grouped together like cobalt and nickel have been
placed withhalogens.
Due to above limitations, Newland law of octave was rejected
MANDELEEV’S PERIODIC TABLE:
He arranged the elements in order of increasing atomic masses, similarity in physical and chemical
properties of element. Properties of hydrides and oxides of different element were studied and elements
with similar properties were grouped together.
He classified the elements in table consisted of vertical columns called groups and horizontal rows
called periods .there were 7 groups in table and group is subdivided into subgroups A and B except
group 7 which has three sets of elements in 4th , 5th , 6th period.
LIMITATIONS OF MENDELEEV, PERIODIC TABLE:
1. Position of hydrogen was not assigned correctly.
2. No separate position has been given to isotopes of an element.
3. Some element having higher atomic mass is placed before the elements with lower atomic mass.

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MODERN PERIODIC TABLE:
Mosely modified the Mandelleve’s periodic table by taking atomic number as the fundamental property
instead of atomic mass.
Modern periodic table consists of 18 vertical columns known as group, and 7 horizontal rows known as
periods .
GROUPS:
Elements in group one is called alkali metals.
Elements in group 2 are called alkaline earth metals.
Elements in group 17 are called halogens.
Group 18 element is called inert gasses or noble gases.
Significance of group in the periodic table is that an element in a group has same number of valance
electron, valency and thus identical chemical properties.
PERIODS
1ST PERIOD – 2 elements and is called very short period.
2nd PERIOD- 8 elements and are called short period.
3rd PERIOD – 8 elements and are called short period.
4th PERIOD – 18 elements and are called long period.
5th PERIOD – 18 elements and are called long period.
6th PERIOD – 32 elements and are called very long period.
7th PERIOD- incomplete period.
The number of shell present in the element indicates the period to which it belongs.
VALENCY:
It is defined as the combing capacity of an atom of an element to acquire noble gas configuration. It is
equal to the number of electron lost, gained or shared during the formation of chemical compound.
ATOMIC SIZE / ATOMIC RADII:
It is defined as the distance from the centre of the nucleus to the outer most cell of atom .it is generally
expressed in pico meter ( pm) .
On moving down the group the atomic radii increases.

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Because on moving down the group a new energy shell is added which increases the distance between
the outermost electron and the nucleus . All though the nucleus charge also increases , but it is
compensated by the additional shell being added thus , increasing the size of the atom .
Across the period the atomic radii decrease. Due to the increase nuclear charge , the pull on the electron
increases and hence, they are pulled closer to the nucleus thus, decreasing the atomic size .
Oxides and its nature. Metal reacts with oxygen to form oxides by loss of electrons. These oxides on
dissolution in water from bases.
REACTIVITY OF ELEMENTS.
Down the group reactivity of metal increases as the tendency to lose electron increases due to the
increased atomic size.
Reactivity of non-metals decreases down the group because of the increased atomic size and the
tendency to gain electron decreases.
On moving across the period the reactivity first increases due to the decreased in the metallic character
and increase in nonmetallic character.
HOTS
Q.1 Why do think the noble gas are placed in a separate group?
Ans. They are present in low concentration in our atmosphere rand have stable outer configuration.
Q.2 Explain the following:
a. Hydrogen is regarded as rogue element in the periodic table.
b. Alkali metals do not form dipositive ions.
Ans.A ). Because Hydrogen resemble alkali metals in some properties and Halogen in some other
properties. Therefore it can be placed either along with alkali metals of group 1 and halogen of group 17
b. Alkali has one electron in the valence shell. By losing the electron, they acquires the stable electron
configuration if the unipositive ions. Once, they achieve the noble gas configuration, these unipositive ions
have no tendency to lose another electron to form dipositive ion. Since the energy required is so large.
Q.3 Write the electronic configuration of the following ion Cl , O, Ca, As.
Ans. The electronic configuration of element and their ions are:
Cl =2,8,7 Cl- = 2,8,8
O=2,6 O2- =2,8
Ca=2,8,8,2 Ca2+ =2,8,8
Al=2,8,3 Al3+ =2,8
Q.4 Atomic number is considered to be a more appropriate parameter than atomic mass for classification of
element in a periodic table. Why?

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Ans. The properties of an elements upon its outer electronics configuration which in turn, depends upon the
number of electrons i.e atomic number .Therefore, atomic number is a more appropriate parameter than
atomic mass.
Q.5 An atom has electronic configuration 2,8,7
a. What is the atomic number of these element.
b.To which of the following elements would it be chemically similar N(7), F(9), P(15), Ar(18).
Ans.a. The electronic configuration of the element is 2,8,7 therefore atomic number of element
2+8+7 =17
b. Since the element has 7 electron in the valence shell .It belong to the halogen family of group 17.So it is
similar to F.
Q.6 Nitrogen (At. No = 7) and Phosphorus (At. No = 15) belong to group 15 of the periodic table .Write the
electronic configuration of these 2 elements, which of these will be more electro negative .Why?
Ans.At. No electronic configuration
N 17 2,5
P 15 2,8,5
Both these element have 5 electron in their respective valance shells and then have a high tendency to
gain 3 more electrons to form negative ion by completing their respective orbitals. Thus both these element
are electro negative. Further since atomic size increase down a group. Therefore Nhas smaller size than P
and hence is more electronegative than P.
Q.7 The position of these element A,B,C in the periodic table are shown below
Period group16 group17
2
3 A
4 B
5 B C
A. State whether C is metal or non-metal.
B. State whether C is more reactive or less reactive than C.
C. Will C be the longer or smaller in size than B.
D. What type of ion will be formed by element C?
Ans. a. Element of group 17 have 7 electron in their respective valance shells and these have a tendency to
complete their respective octet. Thus C which is an element of group 17 is a non-metal.
b. As we move down a group ,the atomic size increases .Therefore the force of attraction of the
nucleus for the incoming electron decreases and hence the reactivity decreases down the group. Since
element C has larger atomic size than element A , therefore C is less reactive than the element A.
c. Element B and C belong to the same period i.e 5th period . As we move from left to right in a period the
nuclear charge increases but the number of shells remains to be the same .Therefore the size decreases from
left to right then the atomic size of C is smaller than that of B.

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d. Since element C has 7 electrons in the valence shell ,therefore it has a high tendency to gain one electron
to complete its octet. Thus element C forms an atom i.e
C + e- = C-
Q.8 A metal M forms an oxide having the formula M2O3 .It belong to 3rd period in the modern periodic
table .Write the atomic number and valency of the metal.
Ans. The formula M2O3 indicates that the valency of M is 3. It has 3 valence electron and belong to group
15 , since it present in 3rd period , the element is Aluminum (Al). The formula of oxide is Al2O3 .
LONG ANSWER QUESTIONS
Q.1 Explain why the number of elements in the period is 8?
Ans .According to 2n2 rule, the maximum number of e- in the third period = 2×32=18.But the last shell
cannot accommodate more than 8 e- .Therefore; the number in the third period is 8.
Q.2 Lithium, Sodium and Potassium have been put in the same group on the basis of their similar chemical
properties:
a) What are those similar properties?
b) What is the usual name of this group or family?
Ans. a) Similar chemical properties of the elements, lithium, sodium and potassium are:-
-All these elements are metals.
-All of these have a valency of one .i.e., they are monovalent .
-All these elements react with water to form alkalis with the evolution of H2 gas.
b) These elements are collectively called alkali metals because they react with water to form alkali.
Q.3 a) An unknown element is given the given the name eka- phosphorus? What does it mean?
b) Why does not element present in a period show similar characteristics?
Ans. a) It means that the element belongs to the same group as phosphorus (Group-15) and is placed after
phosphorus .Moreover, its properties are also similar to those of phosphorus.
b) The properties of the elements are related to their electronic configuration. The element with similar
valence shell electronic configuration show similar properties. Since it changes along a period therefore, the
elements in a period differ in their characteristic.
Q.4 Calcium is an element with atomic number 20.
a) Is it a metal or non-metal?
b)Will its size be more or smaller than that of potassium?
c)Write the formula of its chloride?
Ans. The E.Configuration of Ca :-2,8,8,2
a) Since it has only two valence e-,it is present in group 2.It is a metal.
b) Both potassium and Ca are present in 4th period .Since atomic size decreases along a period
,Calcium is smaller in size.

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c) The valency of Ca is 2.The formula of its chloride is CaCl2.
Q.5Which physical and chemical properties of the elements were used by Mendeleev in creating his
periodic table ?List two observation which posed to Mendeleev’s periodic law?
Ans. The creation of Mendeleev periodic table was based upon certain physical and chemical
properties:
Physical properties: The atomic masses of the elements were taken into account and the element was
arranged in order of increasing atomic masses. The influence some of their physical properties such as
M.P,B.P, Density etc.
Chemical properties: The distribution of the elements into different group was linked with formation of
hydrides by combining with oxygen .This is linked with the valency of the elements.
The two main observations which posed challenge to Mendeleev periodic table are as follows:
a) Position of isotope: Since the isotope of an element differs in their atomic masses, they must be
assigned separate slots or position in the periodic table.
b) Anomalous position of some elements: In the Mendeleev period table, certain element with higher
atomic masses precede or placed before the elements with lower atomic masses .For ex. Ar. Is
placed before the element K.
Q.1 Why are the member of Group1 known as alkali metals?
Ans. Because they react with water to form soluble hydroxide that are called alkali.
Q.2 on which side of the periodic table are the metal located?
Ans .Left and also in the centre of the periodic table.
Q.3Which of the following species is isoelectronic in nature?
i. Ca2+
ii. K
iii. Mg2+
iv. S2-
v. Cl-
Ans.Ca2+,S-,Cl- these have 18 e-.
Q.4 Name three elements which behave as metalloid?
Ans .Arsenic, Antimony, germanium.
Q.5 Two element A and B belong to the same period .What is common in them?
Ans .They have the same number of shells.
Q.6 What is the name given to the elements present in group 17? Why are they so named?
Ans. Elements belonging to group 17 are called Halogens .The word Halogen stands for sea-salt
forming .Since most of the salts present in the sea water are chlorides, bromides, and iodide, that is why the
elements are called Halogens.
Q.7 On the basis of the periodic classification , identify each set belonging to either to group or a period:
i. Na, Mg ,Al
ii. Na ,K ,Rb
iii. B,C,N

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iv. He, Ne ,Ar
Ans. Period
Group
Period
Group
Q.8 What are the definite gaps of the atomic numbers in a group?
Ans.8, 8,18, 18,32
Q.9 What was the criteria used by Mendeleev in creating his periodic table?
Ans. Atomic masses of the elements
Q.10 Name the inert gas which has 2 electrons in the valence shell?
Ans, Helium

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CHAPTER 6 -LIFE PROCESSES
KEY CONCEPTS & GIST OF THE LESSON
 Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, etc.
 Criteria of life- (i) Growth (ii) Movement
 Nutrition- The process in which an organism takes in food, utilizes it to get energy, for growth, repair and
maintenance, etc. and excretes the waste materials from the body.
 Types ofnutrition
1. Autotrophic nutrition(Auto =self: trophos = nourishment) E.g. Plants, Algae, blue green bacteria.
 Energy conversion- Light/Solar energy to Chemical energy
 Role off Chlorophyll- To trap the sun’s energy for photosynthesis
 Environmental Factors- (i) Carbon dioxide (ii) Water(iii) Light (iv) Temperature
 Events/ Steps of photosynthesis-
a) Absorption of light energy by chlorophyll
b) Conversion of light energy to chemical energy & Splitting of water molecule into Hydrogen
& oxygen
c) Reduction of Carbon dioxide to Carbohydrate
 Gaseous exchange- (i) Gas used- Carbon dioxide
(ii) By product - Oxygen
 Source of raw materials-
a) Carbon dioxide –Land plants- Air, Aquatic plants- Water
b) Water & Minerals - Soil
2. Heterotrophic nutrition (Hetero = others: trophos = nourishment) Eg. Animals, some plants and fungi.
 Saprophytic nutrition: Organisms feeds on dead decaying plants or animal’s material.
 Parasitic nutrition: Organisms obtain food from the body of other living organisms (host)

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 Holozoic nutrition: Organism (mostly animals) takes in whole food and then digests it into smaller
particles with enzyme.
 Steps in Holozoic nutrition
a) Ingestion: taking in of food.
b) Digestion: breaking down of complex food into simpler, absorbable form.
c) Assimilation: Utilization of digested food from the body.
d) Egestion: Removing undigested food from the body
 Nutrition in human beings
 Alimentary canal-
Mouth → Oesophagus → Stomach → Small intestine → Large intestine →
Rectum → Anus
Organ Gland Enzyme/Juice Function
Mouth Salivary glands Salivary Amylase Converts starch into sugar
Stomach Gastric glands Gastric juice-
(i) Hydrochloric
acid →
(a) Kills harmful bacteria that
enters with the food.
(a) Makes the medium acidic
for the action of Pepsin

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(ii) Pepsin →
(iii) Mucus →
Digests proteins
Protects the inner lining of the stomach
from the corrosive action of
Hydrochloric acid.
Small intestine 1) Liver
2) Pancreas
(i) Bile juice →
(ii) Pancreatic
Juice
 Amylase →
 Trypsin →
 Lipase →
(a) Makes the medium Alkaline
for the action of Pancreatic
enzymes.
(b) Breaks down large fat
molecules into smaller globules
so that enzymes can act upon
them.
Converts Carbohydrates to glucose
Converts Proteins to Amino acids
Converts Fats into Fatty acids &
Glycerol
 Peristaltic movements- Rhythmic contraction of muscles of the lining of Alimentary canal to push the
food forward.
 Sphincter muscle- Helps in the exit of food from the stomach.
 Villi and microvilli- Small finger like projections on the walls of-
a) Small intestine- To increase the surface area for the absorption of food.
b) Large intestine- For absorption of water.
Respiration
 The process by which digested food is broken down with the help of Oxygen to release energy.
 Types ofrespiration- (i) Aerobic respiration (ii) Anaerobic respiration

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Aerobic respiration Anaerobic respiration
1. Takes place in presence of Oxygen.
2. End products- Carbon dioxide & Water
3. More energy is released.
4. Takes place in Cytoplasm & Mitochondria
5. Complete oxidation of glucose takes place.
6. It occurs in most organisms.
7. Equation-
Glucose → Pyruvate → CO2 + H2O + Energy
1. Takes place in absence of Oxygen.
2. End products- Ethanol & Carbon dioxide
3. Less energy is released.
4. Takes place in only in Cytoplasm.
5. Incomplete oxidation of glucose takes place.
6. It occurs in certain bacteria, yeast & certain
tissues of higher organisms. E.g. In humans
during vigorous exercise, when the demand for
Oxygen is more than the supply, muscle cells
respire anaerobically for some time.
7. Equation-
In Yeast-
Glucose→ Pyruvate→ Ethanol + H2O + Energy
In muscle cells -
Glucose→ Pyruvate→ Lactic acid + Energy
 Some common features of Respiratory organs- (i) Large
surface area- for greater rate of diffusion of respiratory gases. (ii) Thin permeable walls
– to ensure easy diffusion & exchange of gases. (iii) Extensive blood supply- Respiratory
organs are richly supplied with blood vessels for quick transport of gases.

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Mind Map
 Gaseous exchange in plants-
 Process – Diffusion
 Direction of diffusion depends on-
i. Environmental conditions
ii. Requirement of the plant.
 Day time- Carbon dioxide given out during respiration is used for photosynthesis. Therefore only
Oxygen is released,which is a major activity during the day.
 Night time – Only respiration takes place. Therefore only Carbon dioxide is released,which is a
major activity during the night.
 Gaseous exchange in animals-
 Terrestrial animals- take Oxygen from the atmosphere.
 Aquatic animals- take Oxygen dissolved in water. (Oxygen content is low in water,therefore they
breathe faster.
 Human Respiratory system- External
nostrils → Nasalcavity → Trachea→ Bronchi → Bronchioles →Alveoli
 Rings of cartilage present in the throat ensure that the trachea (air passage) does not collapse when
there is less air in it.
 Lungs –
i. Present in the thoracic cavity.
ii. They are spongy, elastic bags consisting of Bronchi,
iii. Bronchioles and Alveoli
Respiration occurs in two phases-
(i) External Respiration- Breathing, which is a mechanical process. (ii)
Internal Respiration - Cellular respiration
 Mechanism ofbreathing – It includes : (i)Inhalation (ii) Exhalation

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 Exchange ofgases-
 Unicellular organisms- By Diffusion
 Animals- As the body size is large, diffusion alone is not enough.
 Respiratory pigments also required.
 Respiratory pigment in human beings is Haemoglobin,
 It has very high affinity for Oxygen.
 Carbon dioxide is more soluble in water than Oxygen, so it Gets
dissolves in blood and is thus transported.
Transportation
 Transportation in human beings-
Blood- (i) It is a fluid connective tissue.
(ii) Components- (1) Fluid medium- Plasma
(2) Red blood corpuscles
(3) White blood corpuscles
(4) Platelets suspended in plasma
(iii) Plasma transports food, Oxygen, Carbon dioxide,
Nitrogenous wastes,etc.
 Functions of blood- (i) Transport of respiratory gases.
(ii) Transport of nutrients.
(iii) Transport of waste products.
(iv) Defence against infection
 Blood vessels- (i) Arteries (ii) Veins (iii) Capillaries
Arteries Veins
1. Thick walled.
2. Deep seated.
3. Carry blood away from the heart.
4. Carry Oxygenated blood.
5. Valves absent.
1. Thin walled.
2. Superficial.
3. Carry blood to the heart.
4. Carry Deoxygenated blood.
5. Valves present

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 Heart- (i) It is a muscular organ, which works as a pump in the circulatory system.
(ii) It has two sides, which are separated by a partition so that the oxygenated and
Deoxygenated blood does not get mixed up.
(iii) It has four chambers-
Two upper chambers called Atria.
Two lower chambers called Ventricles.
 Working of heart-
Left side- (i) Left atrium relaxes & the Oxygenated blood enters in it from
the lungs through the pulmonary vein.
(ii) Left atrium contracts & the blood enters the left ventricle
through the valve.
(iii) Left Ventricle contracts and the blood is pumped into the
largest artery ‘Aorta’ and is carried to all parts of the body.
Right side- (i) Right atrium relaxes & the deoxygenated blood from the body enters it
through superior and inferior Vena cava.
(ii) Right atrium contracts & the blood enters the right Ventricle through
the valve.
(iii) Right Ventricle contracts and the blood is pumped into the Pulmonary
artery and is carried to lungs.
 Valves- Unidirectional to prevent the backward flow of blood.
 Pulmonary vein is the only vein that carries Oxygenated blood.
 Pulmonary artery is the only artery that carries Deoxygenated blood.
 Double circulation in man- because the blood passes through the heart twice in one complete cycle of
the circulation.
 Capillaries- (i) Form the connection between arteries & veins
(ii) Walls are one cell thick only for easy exchange of blood.
 Platelets- Plug the leaks of arteries and veins by clotting the blood.
 Lymph- Extracellular fluid similar to plasma but colourless with lesser protein.
 Function of lymph- (i) Transportation of digested & absorbed fats from
the small intestine.

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(ii) Drains excess fluid from the intercellular spaces
back in the blood.
 Higher animals- E.g., birds, mammals.
 Oxygenated blood & Deoxygenated blood are completely separate for efficient Oxygen supply.
 This is to fulfil higher energy needs and to maintain body temperature (warm blooded animals).
 Amphibians & reptiles- have 3 chambered heat where little mixing of Oxygenated blood & Deoxygenated
blood takes place. Therefore their body temperature varies with the temperature of the environment. (cold
blooded animals)
 Transportation in plants-
 Plants need less energy because they do not move and therefore have a slow transport system
 Transport of water-
 Takes place by xylem tissue present in roots, stem, and leaves and is therefore interconnected.
 Root cells take up ions from the soil, which creates a concentration difference between root and soil. Column
of water therefore rises upwards.
 In very tall plants- transpiration creates a suction pressure,which pulls the water upwards.
 Importance of transpiration-
 Helps in upward movement of water in plants.
 It regulates the temperature in plants.
 Transport of food-
 Takes place by phloem tissue.
 Movement of prepared food in plants is called translocation.
Excretion
 The biological process of removal of nitrogenous metabolic wastes in living organisms.
 Excretion in human beings-
 Organs ofexcretory system- (i) Kidneys (iii) Urinary bladder
(ii) Ureters (iv) Urethra
 Kidneys-
 Two in number
 Bean shaped
 Present in abdomen on either side of the backbone
 Functional unit of kidney is nephron.

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 Glomerulus- Group of capillaries (cluster) present in Bowman’s capsule
to receive blood from renal artery and filters it.
 Bowman’s capsule- Cup shaped structure, which contains glomerulus.
 Convoluted tubule- is long and reabsorbs vital nutrients like glucose, amino acids, salts,
urea and water.
Vital functions ofkidneys- (a) Filtration & removal of Nitrogenous wastes
(b) Reabsorption of vital nutrients
 Ureters- Transport the urine formed in the kidneys to the urinary bladder.
 Urinary bladder- Muscular bag like structure to store urine.
 Urethra- Helps in removal of urine when the Urinary bladder is full.
 Excretion in plants-
 Gaseous wastes- CO2in respiration & O2 in photosynthesis are removed by the process of diffusion.
 Excess water- is removed by transpiration.
 Other wastes- (i) Stored in cellular vacuoles or in leaves, which fall off or as gums,
resins, etc. in old xylem.
HOTS QUESTIONS (SOLVED / UNSOLVED)
Q1. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Ans. The mammals and birds are warm-blooded animals which have high energy needs because they constantly
require energy to maintain their body temperature. It is necessary to separate oxygenated blood and deoxygenated
blood in mammals and birds because such a separation allows a highly efficient supply of oxygen to the body cells
which is required for producing a lot of energy needed by them.
Q2. How is small intestine designed to absorb digested food?
Ans. The inner surface of small intestine has millions of tiny, finger like projections called Villi. The presence of villi
gives the inner walls of the small intestine a very large surface area. The large inner surface area of small intestine
helps in the rapid absorption of the digested food.
LIFE PROCESSES
ORAL QUESTIONS
1. Do plants also need oxygen?
2. How does food passes through alimentary canal?
3. What regulate the exit of food from the stomach into small intestine?
4. In which part of the alimentary canalfood is completely digested absorbed?
5. In which cell organelle breakdown of pyruvate takes place using oxygen?

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6. Which structures stop backward flow of blood in atria and ventricles?
7. The filtered urine is collected in which part of nephron?
8. Which part of the plant excretes some waste substances into the soil?
9. Name the process used to remove urea from the blood.
10. The process by which evaporation of water from the plants mainly through the stomata.
SOLVED QUESTIONS
(1) Due to availability of less water, how does the plant cope up with lack of
water in desert conditions?
(2) After a vigorous exercise, you may experience cramps in your leg
muscles. Why does this happen?
(3) What will happen if carbon monoxide combines with haemoglobin?
(4) Food moves down the gut by peristalsis. Which region of brain controls
peristalsis?
(5) Name the pigment present in plants, which can absorb solar energy.
(6) Name the respiratory organs of (i) fish (ii) mosquito (iii) earthworm
(7) Which of the four chambers of the human heart has the thickest muscular
walls?
(8) What will be the outcome if a farmer floods his field everyday?
(9) Which part of visible spectrum is absorbed by chlorophyll pigments?
(10) How does respiration in plants differ from that in animals?
(11) Name the cartilaginous flap which closes the glottis to check the entry of
food into it during swallowing.
(12) Which equipment is used to facilitate breathing during serious breathing
problems?
(13) Chloroplast are called energy convertors. Explain.
(14) Why is the rate if breathing much faster in aquatic organisms than those of
terrestrial organisms?
(15) Why are glomeruli considered as dialysis bags?
(16) Autotrophs synthesise food for the living world. Justify this statement in one
sentence only interconnecting autotrophs and heterotrophs.
(17)Veins and arteries carry blood. Which of these carry blood?
a) Away from the heart?
b) Back to the heart?
(18) Which of the organs perform the following functions in humans?
1. Absorption of food.
2. Absorption of water
(19) Name the areas in a woody stem through which respiratory exchange of gases
take place.
(20) Tooth enamel is one of the hardest substances in our body. How does it
undergo damage due to eating chocolates and sweets?
(21) A certain tissue in a green plant somehow get blocked and the leaves wilted.
What was the tissue that got blocked?

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(22) Write one feature which is common to each of the following pairs of the
term/organs.
i) glycogen and starch ii) chlorophyll and haemoglobin
iii) gills and lungs iv) arteries and veins.
(23) Why doesn’t the lungs collapse even after forceful expiration?
(24) The two openings of the pharynx, one leading to trachea and the other
leading to oesophagus, lie very close to each other. Yet food we swallow
normally does not enter into our trachea. Why?
(25) How would it affect the digestion of proteins and carbohydrates if the
duodenum of man if there is a blockade in the pancreatic duct?
(26) What do you mean by double circulation of blood?
(27) “If there were no algae there would be no fish in the sea”. Comment.
(28)Write the functions of the following in the digestive process:
(i) Bile
(ii) Bicarbonate secreted by the duodenal wall.
(iii) Pancreatic amylase.
(29) Why is the process of diffusion insufficient to meet the oxygen requirement
of human beings?
(30) Draw a diagram of human alimentary canal showing duodenum, small
intestine, liver and pancreas.
(31) Draw a diagram of the human urinary system and label in it.
a. Kidney
b. Ureter
c. Urinary Bladder
d. Urethra
ANSWERS
Ans-1) They open their stomata at night and stomata remain closed during day time,
to conserve moisture.
Ans-2) The sudden build up of lactic acid in our muscles during vigorous,
exercise, causes muscular cramps in our leg muscles.
Ans-3) If the haemoglobin binds with carbon monoxide strongly, the oxygen will not
be carried with blood leading to death of the organism.
Ans-4) Medulla of hind brain.
Ans-5) Chlorophyll.
Ans-6) Fish - gills
Mosquito – Trachea (air tubes)
Earthworm – moist skin
Ans-7) Right ventricle.
Ans-8) Respiration of plants will be affected because the oxygen present in the
interspaces of the soil will be replaced by water.
Ans-9) Blue and Red light
Ans-10) In plants, all parts like the root, stem, leaves, etc., perform respiration
individually., while in animals, either the general body surface or specific organs like
the skin, gills, lungs, etc., are involved in respiration. The rate of respiration is much
slower in plants than in animals. Unlike animals, there is little transport of gases from
one part of the plant to another.
Ans-11) Epiglottis
Ans-12) Ventilator
Ans-13) Chloroplasts are called energy convertors because they trap the solar energy
and convert it into chemical energy.
Ans-14) The aquatic organisms obtain oxygen dissolved in water. As compared to air,
the availability of oxygen in water is fairly low. Hence, the aquatic organisms have to
breathe faster as compared to the terrestrial organisms.
Ans-15) The main function performed by the glomeruli is selective filtration. They
filter small molecules containing glucose, salts, urea, and liquid serum. Etc. The large

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molecules such as proteins remain in blood. Thus, glomeruli of the kidneys function
as dialysis bags.
Ans-16) The food producers are autotrophs and all the heterotrophs consume the food
produced by the autotrophs directly or indirectly.
Ans-17) a) Arteries carry blood away from the heart.
b) Veins carry blood back to the heart.
Ans-18)
1. Absorption of food takes place in small intestine.
2. Large intestine
Ans-19) In woody stem, the bark has lenticels for gaseous exchange.
Ans-20) The acid is formed in the mouth after a sugary food (chocolates and sweet)
has been taken. This acid lowers the pH in the mouth. Tooth decay starts when the pH
of acid formed in the mouth falls below 5.5. This is because then the acid becomes
strong enough to attack the enamel of our teeth and corrode it.
Ans-21) The tissue that got blocked may be xylem. It is through the xylem that water
and minerals absorbed by roots from the soil are transported to the leaves and other
parts of the plant. So, if xylem is blocked, the leaves will not get the nourishment and
will get wilted.
Ans-22)
i) Carbohydrate (food)
ii) Pigments.
iii) Respiratory organs.
iv) Blood vessels.
Ans-23) Even after forceful expiration to the maximum capacity, some amount of air
remains in the lungs, known as residual volume. So, the lungs doesn’t collapse even
after forceful expiration.
Ans-24) The food does not enter into trachea because during swallowing, the aperture
leading to trachea (glottis) gets covered by a cartilaginous flap called epiglottis and
the food has no other passage except going into the oesophagus.
Ans-25) Duodenum is the region where the pancreatic juice secreted by the pancreas
enters. The enzymes pancreatic amylase and trypsin helps in the digestion of
carbohydrates and proteins. Thus, if there is a blockade, the digestion of
carbohydrates and proteins gets affected.
Ans-26) Blood passes through the heart twice for each cycle of the body.
Ans-27) Algae produce O2 as a result of photosynthesis. This oxygen is utilised by the
fishes in the sea for carrying out respiration. If there were no algae, no oxygen would
have been produced. Thus, fishes might have died.
Ans-28)
1. Bile: It is secreted by the gall bladder and it emulsifies the fats into the
smaller droplets for their easy digestion.
2. It provides alkaline medium in the duodenum which is needed for the action of
pancreatic enzymes of different food components for their digestion.
3. Pancreatic amylase enzyme digests starch and changes it into maltose.
Ans-29) The process of diffusion for carrying O2 to all parts of the body is not
sufficient for larger multicellular organisms like human beings. Hence, respiratory
pigment haemoglobin takes up oxygen from the air and carry it to all the parts of our
body through blood.
Ans-30) Textbook Page No. 99, Figure 6.6
Ans-31) Figure 6.13 Page 110 NCERT

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PUZZLES
1. Across
2. Aerial part which eliminates waste from the plant body
4. Unicellular plant that carryout fermentation.
Down
1. Transports oxygen in the body.
3. Carry impure blood.
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2 3
2. Across
1. Help in respiration in water.
3. Removed through urine.
Down
2. Help to breath in air
3. The process by nitrogenous waste is removed.
4. Organism that takes in food with the help of pseudopodia.
1 2
3 4 5

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2
Label The Diagram Of Respiratory System
 Cross word puzzle- Circulatory system
1 2
3
4 5
6
7
8 9

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3
10
11
Clues for solving the cross word puzzle
ACROSS
3. The only vein that carries
oxygenated blood to the heart
4. The organ which beats
continously to act as a pump for
the transport of blood.
5. The number of chambers in the
human heart.
6. A doctor uses this instrument to
amplify the sound of the heart.
8. The two upper chambers of the
heart.
9. The heart is located on this side
of the chest cavity.
10. The only artery that carries
deoxygenated blood from the
heart.
11. They form the connection
between the arteries and veins
DOWN
1. The number of heart beats per
minute.
2. The two lower chambers of the
heart.
7. The heart is roughly the size of
your ______.

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4
Photosynthesis – Crossword puzzle
Across
1 A plant pigment that absorbs sunlight. (11)
4 The links between the energy that carnivores get
from eating to the energy captured by
photosynthesis. (4,5)
7 Chlorophyll absorbs every color of sunlight
except this. (5)
8 A compound needed for photosynthesis. (6,7)
10 The product of photosynthesis. (5)
Down
2 The process by which plants and some bacteria use
the energy from sunlight to produce sugar. (14)
3 Part of the plant where photosynthesis generally
occurs. (6)
5 A compound needed for photosynthesis. (5)
6 An animal that eats plants. (9)
9 A by-product of photosynthesis. (6)
10 Number of molecules of oxygen produced along
with one molecule of sugar. (3)

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CHAPTER 7 – CONTROL & COORDINATION
KEY CONCEPTS & GIST OF THE LESSON
 Coordination-The working together of various organs of the body of an organism in a proper manner to
produce appropriate reaction to a stimulus is called coordination.
 Stimulus- The changes in the environment to which an organism responds and reacts is called Stimulus
 Control & coordination in animals- takes place by (i) Nervous system & (ii) Endocrine system
 Nervous system
Stimulus → Receptor organ → Sensory nerve → Brain/Spinal cord
↓
Response ← Effecter organ ← Motor nerve
 Endocrine system
Stimulus → Endocrine organ → Secrete hormone → Hormone in blood
↓
Response ← Target organ
 Parts of the Nervous system – (i) Brain (ii) Spinal cord (iii) Nerves (Neurons)
 A Neuron is the structural & functional unit of Nervous system
 Parts of a neuron- (i) Dendrites (ii) Cell body (iii) Axon
 Synapse- Space/junction between two adjacent nerves is called Synapse.
 Transmission of impulse – (i) By Electric impulse (inside the neuron).
(ii) In the form of chemicals (At synapse)
 Reflex action- Spontaneous,involuntary and automatic response to a stimulus to protect us from harmful
situations. Eg. On touching a hot object unknowingly we instantly withdraw our hand.
 Reflex arc - The pathway of the reflex action is called Reflex arc.
Stimulus → Receptor organ → Sensory nerve → Spinal cord →Effector organ→ Response
1. Which are the systems involved in the control and co-ordination in animals?
Important Questions

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The systems involved in the control and co-ordination in animals are the Nervous system, Muscular system and
Endocrine system.
2. Name the receptors of taste and smell.
The receptor of taste is Gustatory receptor and that of smell is Olfactory receptor.
3. What is a nerve impulse?
The information passing through a neuron in the form of electrical and chemical signals is known as a Nerve Impulse.
4. How does a nerve impulse travel through the body?
The information acquired at the dendritic tip of a nerve cell sets off a chemical reaction that creates an electrical
impulse. This impulse travels from the dendrite to the cell body and then along the axon to its end. At the end of the
axon the electrical impulse sets off the release of some chemicals. These chemicals cross the gap or synapse and start
a similar electrical impulse in a dendrite of the next neuron. A similar synapse finally allows the delivery of such
impulse from neurons to other cells such as muscles or glands.
5. What is a synapse?
A Synapse is a gap between two neurons.
6. What happens at a synapse between two neurons?
At the end of the axon the electrical impulse sets off the release of some chemicals. These chemicals cross the gap or
synapse and start a similar electrical impulse in a dendrite of the next neuron.
7. What is reflex action? Give examples.
Reflex action is a quick involuntary response to a stimulus by an effector.
E.g.:
i. withdrawing our hand from a hot object.
ii. Closing the eye when a moving object approaches the eye on a collision-course.
iii. Blinking the eyelids when a moving object approaches the eye
iv. Knee-jerk reflex.
8. What is the difference between a reflex action and walking?
Reflex action is an involuntary action whereas walking is a voluntary action.
9. Draw the structure of a neuron and explain its functions.

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7
Neurons are specialized for conducting information via electrical impulses from one part of the body to the other.
There are three types of neurons:
Sensory neurons:Conducts nerve impulses from sense organs to the brain and spinal cord.
Motor neurons: Conducts impulses from brain and spinal cord to the effectors,i.e. muscles and glands.
Relay neurons: Between the sensory neurons and motor neurons.
10. Draw the neuro-muscular junction and label its parts.
11. Draw a labelled diagram of Brain.
12. Which part of the brain maintains posture and equilibrium of the body?

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Cerebellum maintains posture and equilibrium of the body.
13. Write the functions of the following parts:
i. Fore-brain
ii. Cerebellum
iii. Medulla
i. Fore-brain is the main thinking part of the brain. It has regions which receive sensory impulses from various
receptors. Separate areasof the fore-brain are specialized for hearing, smell, sight and so on. There are association
areas where sensory information is interpreted by putting it together with the information from other receptors as well
as with the information already stored in the memory of the brain. There are centers for motor areas for all muscles.
Information about how to respond to the stimuli is passed on to these motor areas.
ii. Cerebellum is responsible for precision of voluntary actions and maintaining posture and balance of the body.
iii. Medulla controls the involuntary actions including salivation, vomiting, blood pressure, etc.
15. Draw a labelled diagram of a Reflex arc.
16. How do we detect the smell of agarbathi or incense stick?
The olfactory receptors in the nose detect smell by sending nerve impulses to the olfactory centre of the brain.
17. What is the role of the brain in reflex action?
Reflex actions take place without the conscious involvement of the brain. But some of these involuntary responses are
controlled by the mid-brain and hind-brain. In spinal reflexes,quick responses are given but the information is sent to
the brain.
18. How are the brain and spinal cord protected?
The brain is protected by the bony box – Cranium of the skull. The spinal cord is protected by the vertebralcolumn.
In addition to this, the brain and spinal cord are surrounded by membranes (meninges) which form a fluid filled
around the brain. This provides further shock absorption.

5
9
19. What are different parts of human brain?
Fore brain Mid brain Hind brain
(i) Cerebrum
(ii) Thalamus
(iii) Hypothallamus
Connects Fore brain & Hind brain
(i) Cerebellum
(ii) Pons
(iii) Medulla oblongata
 Fore brain-
Cerebrum- (i) Main thinking and largest part of the brain.
(ii) It has 3 main areas-
a. Sensory area- to receive impulses from sense organs via Receptors
b. Motor area- control voluntary movements.
c. Association areas- Reasoning, learning & intelligence.
Thalamus – It relays sensory information to the Cerebrum
Hypothallamus- It forms the link between Nervous system & Endocrine system
Mid brain- It connects fore brain and Hind brain. Controls reflex of eyes & ears
Hind brain-Cerebellum – Controls & coordinates muscular movements, maintaining body posture and
equilibrium.
Pons- Acts as a bridge between brain & spinal cord
Medulla oblongata- Controls involuntary actions like blood pressure,salivation, vomiting, etc.
20. What protects the brain and spinal cord?
(i) Bony outer covering: skull for the brain & vertebral column for the spinal cord.
(ii) Cerebrospinal fluid present in between the three membranes.
21. How nervous tissue acts?
Information → Nervous tissue → Brain Muscles → Causes action
22. Give the path of nerve impulse.
Nerve impulse → Muscle cell → Changes shape due to special proteins
↓
Action caused ← shorter form of muscles ← Change shape & arrangement of cell
 Chemical communication by hormones- (advantages)
(i) Electrical impulses have their limitations because they reach only those cells connected to the
nervous tissue.
(ii) Also the nerve cells cannot generate & transmit impulses continuously.

6
0
(iii) Electrical communication is slower.
 Hormones- (i) Chemical messengers secreted by endocrine glands
(ii) Are secreted in small amounts & may act in nearby places or distant places.
(iii) Do not take part in the reaction & are destroyed immediately.
 Difference between Endocrine glands & Exocrine glands
S. No. Endocrine glands Exocrine glands
1. Ducts absent Ducts present
2. Secrete hormones Secrete enzymes
3. Secreted in blood Secreted in ducts of glands
4. Situated away from the site of action Situated near the site of action
Some glands which act as both endocrine & exocrine (Heterocrine)
Gland Endocrine function Exocrine function
Pancreas Produces insulin & Glucagon
hormone.
Produces digestive enzyme. (pancreatic
amylase)
Testes Produces hormone Testosterone Produces male gametes (reproductive cells)
Ovaries Produces hormone Oestrogen Produces female gametes (reproductive cells)
Endocrine System of
Human

6
1
Important Endocrine glands, the hormone they secrete & their function
Endocrine gland Hormone Function
Pituitary gland Growth hormone Body growth, development of bones & muscles
(If excess- Gigantism)
(If less- Dwarfism)
Thyroid gland Thyroxine Regulates carbohydrate,protein & fat metabolism( If
less- Goitre_
Adrenal Gland Glucocorticoids
&Aldosteron,Adrenalin&
Noradrenalin
Regulates metabolism and acts as neurotransmitters
Pancreas Produces insulin &
Glucagon hormone
Regulates blood sugar levels (if less diabetes is
caused)
Testes in males Produces hormone
Testosterone
Development of secondary male characters like deep
voice, beard, etc.
Ovaries in
females
Produces hormone
Oestrogen
Development of secondary female characters like
mammary glands, menstrual cycle, maintenance of
pregnancy.
.
THIGMONASTYEFFECT OF AUXIN ON PLANT
CELL

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3
Coordination in plants
Only chemical coordination is present in plants.
 Tropic movements- The movements of plants in the direction of stimulus (positive) or away from it
(negative) are called tropic movements. E.g. Phototropism, Geotropism. Chemotropism
 Nastic movements- Movements of plants independent of stimuli are called nastic movements. E.g.-
Touch me not plant leaves close when touched.
 Plant hormones (Phytohormones)-
Examples-
1. Auxins- Help in growth of root & shoot tips.
2. Gibberellins- Help in vegetative growth
3. Cytokinins- Promote cell division
4. Abscissic acid - Inhibits growth & causes wilting (falling) of leaves
7. CONTROL AND CO - ORDINATION
HOTS QUESTIONS (SOLVED / UNSOLVED)
Q1. Which hormone:
1. Prepares the body for action?
2. Controls the amount of sugar (glucose) in blood?
3. Brings about changes in boys at puberty?
4. Brings about changes in girls at puberty?
Ans. a) Adrenaline b) Insulin
c) Testosterone d) Oestrogen
Q2. i) Name the hormone produced by thyroid gland.
ii Which mineral is necessary for the synthesis of the above hormone?
iii Name the disease suffer from the deficiency of this mineral.
iv Write the function of the above hormones?
Q3. What is chemotropism? Give one example of chemotropism.
ORAL QUESTIONS
1. What is the basic unit of nervous system?

6
4
2. How do neuron conduct message from brain to other parts?
3. What do you mean by CNS?
4. What are its main parts?
5. Which part controls reflex action?
6. What are endocrine glands?
7. What is the secretion of endocrine gland called?
8. Name a gland of human body which secretes both enzymes and hormone.
9. Which plant hormone helps in cell division?
10. Which hormones help on stem elongation?
HOT QUESTIONS
Q.1) On touching a hot plate, you suddenly withdraw your hand. Which category of
neurons became active first and which one next?
Q.2) Give one example of plant part.
a. Which is positively hydrotropic as well as positively geotropic.
b. Which is positively phototropic but negatively geotropic.
Q.3) What name is given to the microscopic gap between two adjacent neurons?
Q.4) If we step on something sharp accidently we move our foot away at once .what is
this type of response known as?
Q.5) A part of the hind brain makes possible activities like walking, skating, riding a
bicycle and picking up a pencil.name this part of the hind brain.
Q.6) The neck of a person appears to be swollen.
a. Name the disease this person suffering from.
b. Name the mineral whose deficiency in the diet causes this disease.
Q.7) Name the plant hormone:
(a) which inhibits growth and causes wilting of leaves.
(b) which promotes cell division.
Q.8) Taking the example of heart beat, justify the antagonistic action of the
sympathetic and the parasympathetic nerves.
Q.9) Why is abscisic acid known as stress hormone in plants?
Q.10) Name the part of neuron
(a) where information is acquired.
(b) through which information travels as an electrical impulse.
Q.11) How does the plant shoot bends, when the plant is placed in a room having only
one open window?
Q.12) Who transmits nerve impulse across the synapse?
Q.13) Give a reason to explain why
(a) adrenaline helps in dealing emergency situations?
(b) secretions of growth hormone should be specific in the human body?
Q.14) Why do leaves drop off seasonally?
Q.15) Give reason why endocrine glands release their secretions into the blood?
ANSWERS
Ans.1) On touching a hot plate, first the sensory neurons are activated, which take the
information to the brain or the spinal cord. Next, the motor neurons become active
and bring the impulses from the brain to the muscles. In receiving these impulses, the
muscles contract, and the hand is immediately removed from the hot plate.

6
5
Ans.2) a. roots
b. stem
Ans.3) Synapse
Ans.4) Reflex action
Ans.5) Cerebellum
Ans.6) a. Goitre
b. Iodine
Ans.7) a. Abscisic acid.
b. Cytokinins.
Ans.8) Sympathetic system increases contraction and rhythm and parasympathetic
system decreases contraction and rhythm with respect to heart beat.
Ans.9) Abscisic acid in a plant hormone which inhibits growth. Its effects include
wilting of leaves.
Ans.10) a. Dendrite
b. Axon
Ans.11) When the plant is placed in such a room that has only one open window, the
shoot of the plant bends towards the direction of light. Plant hormone auxin is formed
that diffuses towards the shady side of the shoot and stimulates the cells to live longer
on the side of the shoot which is away from light. In this way the shoot bends towards
the light.
Ans.12) Neurotransmitters.
Ans.13) a. Adrenaline increases the heart beat and breathing rate which results in the
supply of more oxygen to muscles. It reduces the blood to the digestive system and
skin, as a result the blood is further diverted to skeletal muscles. All these responses
together prepare the body to deal with the emergency situations.
b. If growth hormones is secreted in excess during childhood then it leads to
gigantism while the less secretion of this hormone during childhood causes dwarfism.
Ans.14) The leaves drop off seasonally as they stop producing auxins, which normally
prevents the formation of abscission zone that cuts off nutrients and water supply to
leaves.
Ans.15) Endocrine glands are ductless glands and their products have to act at a
distant site.
Therefore, they release their secretions into the blood.
QUIZ
1. Which system of our body is made of organised network for conducting information in the body?
2. Which part of the neuron receives information?
3. What is the name of the neuron which remains between the sensory neuron and the motor neuron?
Where is it located?
4. Which part of the brain helps us to do activities like riding a cycle and walking in a straight line?
5. What are two major types of muscles we have?
6. What causes change in leave of ‘touch me not’ plant?

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7. Which hormone helps us to prepare to combat adverse condition?
8. Name a female sex organ which produces gametes as well as female hormone.
CROSS WORD PUZZLE: NERVOUS SYSTEM
Clues
ACROSS
1. Composed of the brain and spinal cord (3 words).
8. Contains photoreceptors; on the inner posterior portion of eye.
9. "Inside the mouth"
11. Electrical brain activity recorded with scalp or brain electrodes
(abbreviation).
13. Necessary for hearin
17. Neurotransmitter in brain, spinal cord and peripheral nervous system
(abbreviation).
18. Outermost layer of meninges.
19. Neurotransmitter lacking in patients with Parkinson's disease.
21. Supportive cells of the nervous system; "glue".
22. Nerve cell.
23. Photoreceptor that is not used for color vision.

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7
24. Photoreceptor that is used for color vision.
26. The sense of hearing.
29. Opposite of "Yes"
30. Junction between two neurons.
DOWN
1. In the brain, it is the outermost layer of the gray matter.
2. The fifth cranial nerve.
3. The middle layer of the meninges.
4. The part of the cell containing chromosomes.
5. Period of sleep when dreams occur (abbreviation).
6. The second cranial nerve.
7. Fat-like substance that surrounds some axons.
10. The first cranial nerve.
12. Fluid that fills the ventricles (abbreviation).
14. Part of neuron that takes information TO the cell body.
16. Short for "mother".
18. Electrical brain activity between 2 and 4 Hz.
20. Part of neuron that takes information AWAY from the cell body.
22. A short written letter.
24. Abbreviation for 1 across.
25. Organ for vision.
27. Opposite of "off".
28. Opposite of "yes".
ANSWERS: CROSS WORD PUZZLE: NERVOUS SYSTEM

KV Sanghatan Science Study Material Class X

KV Sanghatan Science Study Material Class X

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