This document discusses elements, compounds, and mixtures. It defines elements as pure substances made of only one type of atom that cannot be separated into simpler substances. Compounds are made of two or more elements chemically bonded together in fixed ratios. Mixtures contain two or more substances mixed but not chemically combined. The document classifies elements and provides examples, discusses properties of compounds and how to write chemical formulas, and describes different types of mixtures and methods to separate them.

1. Elements , compounds and
mixture
CHAPTER -3

2. Matter
Living
Plant Animals
Non living
Pure
Elements
Metal Non metal Metalloids Nobel gases
Compound
Mixture
Homogeneous Heterogeneous

3. Elements
 Any pure substance which cannot be broken into two or more simpler substances by any chemical
means is called element .
 Chemist have discovered 114 elements so far .
 82 normal elements (normal element – which do not give out harmful radiation )
 32 radioactive elements (which give out harmful radiation )

4. Example of elements

5. Characteristics of elements
 Elements are pure substances that consist of only one kind of atoms .
 Each element has its own unique properties .
 The atoms of an element exhibit the same properties as the element .
 Elements cannot be separated or broken down into simpler component by
physical or chemical methods.

6. Classification of element
Elements
Metals Non-metals
Inert gas or
noble gas

7. Metals
 An element is a metal if it has lustre is a good conductance of heat and electricitry is malleable and ductile and
has high melting point and boiling point .
 {We have read few terms in this definition :
 Lustre :Metals in their pure state have a shining surface. This property is called metallic lustre. Metals can be
polished to give high reflective surface.
 Good conductance :good electrical and thermal conductivity.
 Malleable :ductility is the ability of a solid material to deform under tensile stress. Practically, a ductile material
is a material that can easily be stretched into a wire when pulled
 Ductile :A malleable material is one in which a thin sheet can be easily formed by hammering or rolling. In
other words, the material has the ability to deform under compressive stress.
 Melting point :The temperature which causes solids to melt. Same as freezing point.
 freezing point: The temperature at which liquids become solids. Same as melting point.
 Boiling point :The temperature which causes liquid to boil.

8.  Each element is denoted by first letter of its name.(in English or latin language )is
capital letter .
 When the first letter name of several element is same then the element is denoted
by two letters.
 First letter of the symbol is in capital letter , followed by the second or third letter
in the name of element in small letter .
Symbol of metals

9. Name in English Name in language other
than English
Symbol
1.Sodium Natrium Na
2. Magnesium Mg
3. Aluminium Al
4. Potassium Kallium K
5. Calcium Ca
6.Chromium Cr
7.Manganese Mn
8.Iron Ferrum Fe
9. Nickel Ni
10. Copper Cuprum Cu
11.Zinc Zn
12. Silver Argentum Ag
13.Platinum Pt
14.Gold Aurum Au
15. Lead Plumbum Pb
16.Mercury Hydragyrum Hg

10. Non metals
 An element is a non metal if it is a soft solid, liquid or gas at room temperature
has no lustre is bad conductor of heat and electricity is non malleable and non
ductile and has low melting point and boiling point .

11. Non metal State at room temp . Symbol
1.Hydrogen Gas H
2.Nitrogen Gas N
3.Oxygen Gas O
4.Fluorine Gas F
5.Chlorine Gas Cl
6.Bromine Liquid Br
7. Iodine Solid I
8.Carbon Solid C
9.Sulphur Solid S
10.Phosphorous Solid P
11. Silicon Solid Si

12. Nobel gas
 The elements found in air in small traces in gaseous state , which do not react
chemically with any other element are called noble gases .( as found in small
traces called rare gases )

13. Noble gas Symbol
Helium He
Neon Ne
Argon Ar
Krypton Kr
Xenon Xe
Radon Rn

14. Compounds
 When the molecule of a pure substance which contains two or more atoms of different element combined
together in a definite ratio , then it is said to be a molecule of a compound .
 A molecule of a compound can be broken into elements by chemical means .
 For example , molecule of water contrains two atoms of hydrogen and one atom of oxygen .
 It can be broken into elements of hydrogen and oxygen by passing electric currents through it .

15. Formula of compound
 Information that we get from the formula of a compound:
 It tells us about which elements are present in a compound .
 It tells us the number of atoms of each element present in a compound .

16. Formula
 A symbolic representation of one molecule of a compound representing the
number of atoms of various elements present in it is called formula .

17. Name of a compound Formula
Hydrochloric acid HCl
Nitric acid HNO3
Sulphuric acid H2SO4
Sodium hydroxide NaOH
Calcium oxide CaO
Sodium carbonate (washing soda ) Na2CO3
Calcium carbonate CaCO3
Sodium bicarbonate (baking soda ) NaHCO3
Ferrous sulphide (iron sulphide ) FeS
Sodium chloride NaCl
Potassium nitrate KNO3
Aluminium chloride AlCl3
Silver nitrate AgNO3
Copper sulphate (blue vitrol ) CuSO4

18. Gas Formula
Carbon dioxide CO2
Carbon monoxide CO
Sulphur dioxide SO2
Sulphur trioxide SO3
Hydrochloric acid gas HCl
Nitrogen dioxide NO2
Methane CH4
Steam H2O

19. Metal sulphide formula
Calcium sulphide CaS
Magnesium sulphide MgS
Zinc sulphide ZnS
Lead sulphide PbS
Copper sulphide CuS
Mercury sulphide HgS

20. How to read information in the formula of
a compound ?
 i) The symbols in a formula can be prefixed or suffixed by a numeral.When the numeral is written on the left
hand side before the formula , it represents number of molecules of the compound , and hence the number
of atoms present in each molecule .For example;
 When we write 2S ,3Cl or 4Al, it means two atoms of sulphur , three atoms of chlorine, 4 atoms of
aluminium .
ii) When the numeral is written on the write bottom side of the symbol , it represents the number of atoms in
one molecule of a compound .For example :
When we write H2, O2, it means that one molecule of hydrogen has 2 atoms in it . Similarly one molecule of
oxygen has two atoms of oxygen in it .

21. Valency
 The no of electrons donated or accepted by an atom of an element so as to have
8 electrons in its outermost shell /orbit is called valency .

22. Positive valency
 Metals have 1-3 electrons in their outermost shell which they tends to donate to
the other elements .In donating to the other element , the no of protons increases
as compared to the number of protons . Thus the metallic ion gets positively
charged .
 The no of electrons donated by an atom is equal to its electropositive
valency .
 Monovalent electropositive valency :The metallic ion formed by the donation
of only one electron from their outermost shell /orbit are called
monopositive ions .

23. Monovalent
ion
Hydrogen Sodium Potassium Ammonium
formula H+ Na+ K+ NH4
+

24. Bivalent valency
 The metallic ion formed by the donation of only two electron from their
outermost shell /orbit are called .bivalent electropositive ions

25. Bivalent
ion
Magnesiu
m
calcium Zinc barium Lead
Formula Mg+2 Ca+2 Zn+2 Ba+2 Pb+2

26. Trivalent valency
 The metallic ion formed by the donation of only three electron from their
outermost shell /orbit are called trivalent electropositive ions .

27. Variable valency
 Sometimes it has been found that the elements (metallic ) can losde electrons
from their innermost orbit along with outermost orbit in certain experimental
condition .
 Exampple : irom can lose 2 electron from its outermost shell in normal condition
and form (Fe+2)where as in certain special experimental condition it lose electrons
from its innermost shell as well as from outermost shell and forms (Fe +3).In such
situation the element exhibits variable valency .

28. Naming of variable valency
 If an element exhibits two electropositive valency then , lower valency a suffix –
ous is attached at the end of the name of metal .For higher valency a suffix –ic is
attached at the end of the name of the metal .Example : The latin name of iron is
ferrum , for lower valency it is named as ferrous(Fe+2) .
 For higher valency it is named as ferric (Fe+3 )

29. metal Name and lower
valency
Name and higher
vaelncy
Iron (ferrum ) Ferrous Ferric
Copper (cuprum ) Cuprous Cupric
Silver (argentum ) Argentous Argentic
Mercury Mercurous Mercuric

30. Negative valency
 Non-metals have 4 to 7 electrons in their outermost shell.They tends to
accept electrons from other elements so as to have eight electrons in their
outermost shell .
 The no. of electrons accepted by an atom of an elewment is its
electronegative valency .
 The group of 2 or more non-metals which has negative charge on it is called
radical .

31. Monovalent electronegative ion or
radicals
 An ion or a radical formed by the acceptance of an electron is called
monovalent electronegative ion or radical.

32. Ion or radical Formula
1. Chloride Cl-
2. Bromide Br-
3. Iodide I -
4. Hydride H-
5. Nitrite NO2
-
6. Nitrate NO3
-
7. Bicarbonate or hydrogen carbonate HCO3
-
8. Bisulphide or hydrogen sulphide HS-
9.Bisulphite or hydrogen sulphite HSO3
-
10.Bisulphate or hydrogen sulphate HSO4
-
11. Hydroxide OH-
12. Acetate CH3COO-

33. Bivalent electronegative ion or radicals
 An ion or radical formed by the acceptance of 2 electrons is called bivalent
electronegative ion or radical.

34. Ion or radical Formula
1. Sulphate SO4
-2
2. Peroxide O2
-2
3. Sulphite SO3
-2
4. Carbonate CO3
-2
5. Sulphide S-2
6. Silicate SiO3
-2
7. Oxide O-2
8. Zincate ZnO2
-2

35. Trivalent electronegative ion or radical
 An ion or radical formed by the acceptance of 3 electrons is called trivalent
ion or radicals.

36. Ion or radiacals Formula
Phosphate PO4
_3
Phosphite PO3
_3
Phosphide P_3
Nitride N_3

37. Writing of formula of compound

39. Mixtures
 A mixture is a substance that contains two or more different substances (elements
, compounds or both ) mixed together in such a way that no chemical change
occur between them .
 The different types of substances present in a mixture are called its components or
its constituents .
 Air , tap water , oil in water , sugar in water , soil , alloy are a few examples of
mixture .

40. Characteristics of mixture
 A mixture does not exhibit any characteristic property of its own. The components
of a mixture do not lose their properties and thus retain their original properties in
the mixture .
 In a mixture the components are not present in fixed proportion or ratio .
 The components of a mixture can be separated easi.ly through physical methods
of separation .
 Mixtures are not pure substances as they contain more than one type of
component .

41. Compounds and mixture

42. Types of mixture
 On the basis of distribution of components :
 A) Homogeneous mixture – When the components in a mixture are distributed uniformly and
cannot be seen distinctly called a homogeneous mixture .
 The properties of a homogeneous mixture remain the same in all parts of the mixture . Air is a
homogeneous mixture .
 Solution , alloy are examples of homogeneous mixture .
 In a solution , the solute particles (salt or sugar ) dissolve in a solvent (water ) completely .Thus ,
the individual component in a homogeneous mixture cannot be seen distinctly .
 Example: salt solution , sea water , orange juice etc .
 Alloy is a mixture of two or more metals or metals and non metals .
 Example : stainless steel , bronze , brass etc .

43. Contd .
 Heterogeneous mixture : When the components that make up a mixture are not
distributed uniformly and can be seen distinctly is called a heterogeneous
mixture .
 The properties of a heterogeneous mixture differ in different parts of the mixture .
 Smoke is a heterogeneous mixture .
 Suspension and emulsion are examples of heterogeneous mixtures .

44. Suspension
 A suspension contains small , undissolved solid particles suspended in a fluid ( a
liquid or a gas ) .
 These particles can be seen distinctly .
 When the suspension is kept undisturbed , the particles settle down .
 Example ; chalk water , muddy water .

45. Emulsion
 An emulsion is a mixture of two or more immiscible liquid (Liquid that do not mix
together completely and formed separate layer when mixed )
 An emulsion of oil and water is an example of a heterogeneous mixture in which
oil and water are seen as two separate layer.

46. Mixture
Solid-solid
mixture
Ex- salt and pepper , husk in rice
Solid-liquid
mixture
Ex-sugar solution, sand and water etc
Liquid –liquid
mixture
Ex-water and milk , oil and water

47. Method of seperating mixtures
 A) separating solid –solid mixtures :
 i) Sublimation :The process in which a solid directly changes into its
gaseous state without passing through its liquid state is called sublimation.
 Principle : This method is used when a mixture contains a component that
can sublime .
 https://youtu.be/6YYrcHLckMw

49. Method of seperating mixtures
 A) separating solid –solid mixtures
 Magnetic separation – If you move a magnet through a mixture of iron
filings and chalk , the iron particles attach themselves to the magnet .
 Chalk is not attracted by a magnet and its particles are left behind .
 A mixture iron and chalk separated by this way .
 A method such as this in which a magnet is used to separate the components
of a mixture called magnetic separation .
https://youtu.be/MGLRMRU1d-8

50.  Seperating solid –liquid mixture
 EVAPORATION :The process in which liquid changes into gaseous state is called
evaporation .
 PRINCIPLE :This method involves the evaporation of the liquid component from
the mixture while the solid component is left behind .
 https://youtu.be/PtqlB1fttcs
Method of seperating mixtures

51. Method of seperating mixtures
 Seperating solid –liquid mixture
 Crystallisation :While evaporating a solution , a stage comes when the amount
of solvent become liquid , called concentrated solution .
 When it is allowed to cool slowly , crystals of the substance dissolved start
separating , called crystallisation .
 Used to obtain pure form.
 https://youtu.be/QdwKhbtzsug

52. Method of seperating mixtures
 SEPERATION SOLID-LIQUID MIXTURES :
 1. heat the mixture in the round bottom flask .
 2. The mixture starts to boil and the liquid component
(water ) evaporates .
 3. The vapours pass through the condenser , where they
cool and condense to form the pure liquid that gets
collected in the beaker .
 4. The solid components (salts ) is left behind .
CONCLUSION : Distillation is used to obtain pure liquid
from a solid liquid mixture .
https://youtu.be/mP4Hgui-g6U

53. Method of seperating mixtures
 SEPERATING LIQUID –LIQUID MIXTURES :
 Seperating funnel –A separating funnel is used
to separate a mixture of immiscible liquids ..
 PRINCIPLE : This method is based on the
principle that in immiscible liquids , the lighter
liquid floats above the layer of the heavier
liquid .
 A mixture of oil and water can be separated
using this technique.
 https://youtu.be/7oqLUIHpqOc

54. Method of seperating mixtures
 SEPERATION OF LIQUID-LIQUID MIXTURE :
 FRActional distillation :
 It is a method used to separate a mixture
of miscible liquid (liquids that can be
mixed together completely ).
 PRINCIPLE : This method is based on the
difference in the boiling point of the liquid
components to be separated.
 This method is used to get petroleum
products from crudfe loil , such as petrol ,
kerosene , diesel , gasoline , tar etc .
 https://youtu.be/Ag9Dym0Fwd0

55. Method of seperating mixtures
 SEPERATION OF LIQUID-LIQUID MIXTURE :
 PRINCIPLE : Based on the adsorption .[ a solid / liquid substance (adsorbate )form a layer on the
surface of another substance (usually a solid ) called adsorbent { aluminium oxide , silicon
dioxoide , cellulose } is used as an adsorbent .
 Using paper technique (whatman paper) called paper chromatography .
 When we place a solution of a mixture over an adsorbent , the different components of the
mixture get adsorbed to different extents .
 So, they move with different speeds on the surface of the adsorbent .
 It is the solvent that drives the solute on the adsorbent i.e chromatographic paper.
 Solvent used : water-acetone , water –alcohol etc.
 The adsorbent is called stationary phase , the solution called mobile phase , and the band of
colours obtained on the paper is called a chromatogram.