Metals and non metals class X cbse science

1. METALS AND NON METALS

2. 1a) Physical properties of metals :-
● Metals are solids. (except mercury)
● Metals are hard. (except Lithium, Potassium, Sodium)
● Metals have metallic lustre. (shine)
● Metals are malleable. (can be beaten into thin sheets)
● Metals are ductile. (can be drawn into wires)
● Metals have high melting points. (Gallium and Ceasium
have low melting points. They melt in the palm of the
hand)
● Metals have high boiling points.
● Metals are good conductors of heat. ( Best conductors
are silver and copper. Poor conductors are Lead and
Mercury)
● Metals are good conductors of electricity. ( Best
conductors are Silver and Copper)
● Metals are sonorus. (produce sound when
beaten)

3. b) Physical properties of non metals :-
● Non metals may be solids, liquids or gases. (Solids –
Carbon, Sulphur, Phosphorus etc. Liquid – Bromine,
Gases – Oxygen, Hydrogen, Nitrogen etc.)
● Non metals are soft. (except diamond which is the hardest
natural substance)
● Non metals do not have lustre.( except iodine cryatals)
● Non metals are not malleable.
● Non metals are not ductile.
● Non metals which are solids and liquids have low melting
points.
● Non metals which are solids and liquids have low boiling
points.
● Non metals are bad conductors of heat.
● Non metals are bad conductors of electricity. (except
graphite)
● Non metals are not sonorus.

4. 2) Chemical properties of metals :-
i) Reaction with oxygen :-
Metals react with oxygen to form metal oxides.
When copper is heated it combines with oxygen to form copper
oxide. 2Cu + O2
2CuO
When aluminium is heated it combines with oxygen to form
aluminium
oxide. 4Al + 3O2
2Al2
O3
Some metal oxides are basic oxides because they react with water
to form bases.
4Na + O2
2Na2
O
Na2
O + H2
O
2NaOH K+ O2
K2
O
K2
O + H2
O 2KOH
Some metal oxides show acidic and basic properties. They are
called amphoteric oxides. Eg :- Aluminium oxide, Zinc oxide etc.
2AlCl3
+ 3H2
O
Al2
O3
+ 6HCl
(basic)
Al2
O3
+ NaOH
(acidic)
NaAlO2
+ H2
O
(Sodium aluminate)

5. The reactivity of different metals with oxygen is different :-
● Metals like potassium and sodium react vigorously with
oxygen and catch fire if kept in open. Hence they are
stored in kerosene to prevent burning.
● If magnesium is heated, it burns with a bright flame.
● If iron is heated it glows brightly.
● If copper is heated it does not burn but forms a black
coating of copper oxide.
● Silver and gold does not react with oxygen even at high
temperature.
● Some metals like magnesium, aluminium, zinc, lead
etc. forms an oxide layer over it which prevents further
oxidation. They are called self protecting metals.

6. ii) Reaction with water :-
Metals react with water to form metal oxides or metal hydroxides and
hydrogen.
2Na + 2H2
O
2K + H2
O
Ca + H2
O
2Al + 3H2
O
3Fe + 4H2
O
2NaOH +
H2
2KOH + H2
Ca(OH)2
+
H2
Al2
O3
+
H2
Fe2
O3
+
4H2
The reactivity of different metals with water is different :-
- Sodium and potassium react violently with cold water to form
sodium hydroxide and hydrogen and catches fire.
- Calcium reacts less violently with water to form calcium hydroxide
and water and does not catch fire.
- Magnesium reacts only with hot water to form magnesium
hydroxide and hydrogen.
- Metals like aluminium, iron and zinc react only with steam to form
the metal oxides and hydrogen.
- Metals like lead, copper, silver and gold do not react with water.

7. iii) Reaction with acids :-
Metals react with dilute acids to form salts and hydrogen.
Mg + 2HCl
2Al + 6 HCl
MgCl2
+
H2
2AlCl3
+
3H2
ZnCl2
+
H2
Zn + 2HCl
Fe + 2HCl FeCl2
+ H2
The reactivity varies from metal to metal. For the above
metals the decreasing order of reactivity is Mg > Al > Zn > Fe.
Copper, silver and gold do not react with dilute HCl.
Hydrogen gas is not evolved when metals react with
nitric acid (HNO3
) because it is a strong oxidising agent and
it oxidises the H2
produced to water and is itself reduced to
oxides of nitrogen.
3Cu + 8HNO3
3Cu(NO3
)2
+ 4H2
O + 2NO2

8. iv) Reaction of metals with metal salt solutions :-
A more reactive metal displaces a less reactive metal from its
salt solution. (Displacement reaction)
Magnesium displaces copper from copper sulphate
solution. Mg + CuSO4
MgSO4
+
Cu
Zinc displaces copper from copper sulphate solution.
Zn + CuSO4
ZnSO4
+ Cu
Iron displaces copper from copper sulphate
solution Fe + CuSO4
FeSO4
+ Cu after 15 – 20 minutes

9. 3) Reactivity series of metals :-
The arranging of metals in the decreasing order of their
reactivity is called reactivity series of metals.
K -
Potassium Na
- Sodium
Ca - Calcium
Mg -
Magnesium Al
-
Aluminium Zn
- Zinc
Fe - Iron
Pb -
Lead
H -
Hydrogen
Most reactive
Reactivity decreases
Cu -
Copper Hg -
Mercury Ag -
Silver Au -
Gold
Least reactive

10. 4) How do metals an non metals
react ?
Metals :- lose electrons and become positive ions. So they
are called electropositive elements.
Eg :- The atomic number of sodium is 11, its electronic
configuration is
2,8,1, it has 1 valence electron. It loses 1 electron and forms a
sodium
ion Na +
Na
AN = 11
E
C =
2,8,1
Mg
AN = 12
EC
= 2,8,2
Na +
+ 1 e-
2,8
Mg 2+
+ 2 e-
2,8
Non metals :- gain electrons and become negative ions. So
they are called electro negative elements.
Eg:- The atomic number of chlorine is 17, its electronic
configuration is
2,8,7, it has 7 valence. It gains 1 electron and forms a chloride ion
Cl - Cl -
2,8,8
O 2-
Cl + 1 e-
AN = 17
EC =
2,8,7

11. 5a) Formation of sodium chloride molecule – NaCl
Na
xx
Cl
xx
NaCl
AN = 17
EC = 2,8,7
The atomic number of Na is 11, its electronic
configuration is 2,8,1, it has 1 valence electron, it loses 1
electron to form Na +
ion. The atomic number of Cl is 17, its
electronic configuration is 2,8,7, it has 7 valence electrons,
it gains 1 electron to form Cl -
ion. Then the attraction
between the Na +
ion and Cl -
ion results in the
formation of sodium chloride molecule – NaCl.
xx
x x
Na . +
Cl x
xx
AN = 11
EC = 2,8,1
.
x x
x
+ -

12. b) Formation of Magnesium chloride molecule – MgCl2
Mg Mg 2+
+ 2e -
AN = 12
EC = 2,8,2
Cl + 1e -
2,8
Cl -
AN = 17
EC = 2,8,7 2,8,8
Mg + Mg MgCl2
The AN of Mg is 12, its EC is 2,8,2, it has 2 valence electrons, it
loses 2 electrons to form Mg 2+
. The AN of Cl is 17, its EC is 2,8,7, it
has 7
valence electrons, it gains 1 electron to form Cl -
. Then the attraction
2+ -
. x
x
x
xx
x x
x
xx
x
Cl x
x Cl x
2+
-
x
xx
x
x
.
-
x
x
x
x
.
Cl
x
x
xx
Cl x

13. 6) Ionic compounds (Electrovalent compounds) :-
Ionic compounds are compounds formed by the transfer of
electrons from a metal to a non metal.
Properties of ionic compounds :-
i) They are formed by the transfer of electrons and are made up
of ions.
ii)They are crystalline solids.
iii)They have high melting points and boiling points.
iv) They are soluble in water but insoluble in organic solvents (like
petrol, kerosene etc.)
v) They conduct electricity in molten state or in solution.

14. 7a) Occurence of metals :-
Some metals like gold, silver, platinum etc are found in the free
state in the earth’s crust because they are least reactive. Most
metals are found as oxides, carbonates, sulphides, halides etc.
Minerals :- are elements or compounds which occur naturally
inside the earth’s crust.
Ore :- is a mineral from which metals can be extracted
profitably.
Gangue :- is the impurities present in the ore like rock
particles, sand particles, clay particles etc.
b) Extraction of metals from their ores :-
Metals are extracted from their ores in three main steps. They
are :-
i) Concentration of the ore (Enrichment of the ore).
ii) Reduction to the metal.
iii) Refining (Purification of the metal).
Concentration of the ore :- is the removal of gangue

15. 8) Steps involved in the extraction of metals from their
ores :-
Metals of
high reactivity
Metals of
medium reactivity
Metals of
low reactivity
Electrolysis of
molten ore Carbonate ore Sulphide ore Sulphide ore
Pure metal Calcination Roasting Roasting
Oxide of metal Metal
Reduction to metal Refining
Refining
Ore

16. i) Extraction of metals low in the activity series :-
Metals which are low in the activity series can be
reduced to the metals by heating in the presence of oxygen
(Roasting).
Eg :- Mercury is obtained from its ore Cinnabar (HgS) by
heating in the presence of oxygen. When it is heated in the
presence of oxygen it is first converted into mercuric oxide
(HgO) and on further heating it is reduced to mercury.
2HgS + 3O 2HgO + 2O2
2HgO 2Hg + O2
Copper is obtained from its sulphide ore (CuS) by
heating in the presence of oxygen.
2CuS + 3O2
2Cu O + 2SO
2 2
2Cu2
O + Cu2
S 6Cu + SO2
heat
h2
eat
heat
heat

17. ii) Extraction of metals in the middle of the activity
series :-
Metals in the middle of the activity series like Zn, Fe, Pb, are found
as oxide, sulphide or carbonate ores.
It is easier to obtain metals from their oxides than from their
sulphides or carbonates. So non oxide ores are converted into oxide
form before reduction. Non oxide ores can be converted into oxide form
by roasting or calcination.
Roasting :- is heating of an ore in the presence of oxygen. It is
used to convert suphide ores into oxide form.
Eg :- 2 ZnS + 3O 2 ZnO + 2SO
2 2
Calcination :- is heating of an ore in the absence of oxygen. It is used
to convert sulphide ores into oxide form.
Eg :- ZnCO ZnO + CO
3 2
The oxide ore is then reduced to the metal by heating with a
reducing agent. The most common reducing agent is coke (carbon).
Eg :- ZnO + C Zn + CO
heat
heat
heat

18. Thermit reactions :-
Sometimes reactive metals like Na, Ca, Al etc. are used
as reducing agents to obtain metals from their oxides.
Mn + 3Al2
O3
+ Heat (Manganese)
Eg :- 3MnO2
+
4Al
(Manganese
dioxide)
The reaction between metal oxides and aluminium is
highly exothermic and the metals are obtained in molten
state. Such reactions are called thermit reactions.
The reaction between iron oxide and aluminium
produces molten iron. This reaction is used to join rail
tracks, broken machine parts etc.
Fe2
O3
+ 2Al Al2
O3
+ 2Fe +
Heat

19. GENERAL

20. iii) Extraction of metals at the top of the activity series :-
Metals at the top of the activity series like K, Na, Ca, Al etc.
cannot be obtained from their ores by simple heating or by heating
with reducing agents. They are obtained by electrolytic reduction of
their molten chlorides.
Eg :- When electric current is passed through molten sodium
chloride, sodium metal is deposited at the cathode and chlorine gas is
deposited at the anode.
At cathode :- Na +
+ e -
Na (Sodium metal)
-
At anode :- 2Cl -
Cl + 2e (Chlorine
gas)
2

21. 9) Refining of metals :-
The removal of impurities from the metal to obtain the pure metal
is called refining of metals. The most common method for refining of
metals is electrolytic refining.
In this method a block of the impure metal is made the anode and a
thin sheet of the pure metal is made the cathode. The electrolyte is a
salt solution of the metal to be purified.
Eg :- In the electrolytic refining of copper, a block of impure copper
is made the anode and a thin sheet of pure copper is made the cathode.
The electrolyte is acidified copper sulphate solution. When electric
current is passed through the electrolyte, pure copper from the anode
is deposited at the cathode and the impurities settle down as anode
mud.

22. 10a) Corrosion :-
Corrosion is the damage caused to metals due to the reaction of metals
with oxygen, moisture, carbon dioxide etc.
Eg :- Formation of brown coating of rust over iron.
Formation of green coating of basic copper carbonate over
copper. Formation of black coating of silver sulphide over silver.
To show that air and moisture are necessary for the rusting of iron :-
Take three test tubes marked 1,2,3 and put iron nails in each of them. Put some
anhydrous calcium chloride in test tube 1 to absorb moisture. Pour some boiled distilled
water in test tube 2 and pour some oil over it to prevent air into the test tube. Pour
some water in test tube 3. Cork the test tubes and leave them for a few days. The nails in
test tube 1 does not get rusted because it had only air and no water. The nails in test
tube 2 does not rust because it had only water and no air. The nails in test tube 3 gets
rusted because it had air and water.

23. b) Prevention of corrosion :-
Corrosion of metals can be prevented by :-
i) Applying oil or grease.
ii) Applying paint.
iii) By galvanisation. (Coating with zinc)
iv) By tinning. (Coating with tin)
v) By electroplating. (Coating a less reactive metal like chromium)
vi) By alloying. (Making alloys)
c) Alloy :-
An alloy is a homogeneous mixture of a metal with other metals or
non metal.
Eg :- Steel – iron, carbon
Stainless steel – iron, carbon, cobalt,
nickel Brass – copper, zinc
Bronze – copper, tin
Solder – Lead, tin (used for welding electrical wires together)
If one of the metals in an alloy is mercury, it is called an amalgam.