Metals react with oxygen, water, and acids to form metal oxides, hydroxides, or salts. They lose electrons and become positively charged ions. Non-metals react with oxygen to form non-metal oxides, gaining electrons and becoming negatively charged ions. Corrosion occurs as metals react with substances like oxygen and water in the air, forming coatings or rust. Corrosion can be prevented by applying protective coatings like oil, paint, zinc plating, or by alloying metals.

1. Efforts By –
Arundhati Gupta
Class X F

3. 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 Caesium 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 sonorous. (produce sound when beaten)

5. 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 crystals)
• 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.

7. 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 2Al2O3

8. Reaction with Water
Metals react with water to form metal oxides or metal
hydroxides and hydrogen.
2Na + 2H2O 2NaOH + H2
2K + H2O 2KOH + H2
Ca + H2O Ca(OH)2 + H2
2Al + 3H2O Al2O3 + H2
3Fe + 4H2O Fe3O4 + 4H2

9. Reaction with Acids
Metals react with dilute acids to form salts and hydrogen.
Mg + 2HCl MgCl2 + H2
2Al + 6HCl 2AlCl3 + 3H2
Zn + 2HCl ZnCl2 + H2
Fe + 2HCl FeCl2 + H2

10. 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

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

13. Reaction with Oxygen
Non Metals react with oxygen to form non metallic oxides.
When sulphur is heated it combines with oxygen to form
sulphur dioxide.
S + O2 SO2
When carbon is heated it combines with oxygen to form
carbon dioxide.
C + O2 CO2

14. Reaction with Water
Generally, non-metals do not react with water though
they may be very reactive in air. Such non-metals are
stored in water. For example, phosphorus is a very
reactive non-metal. It catches fire if exposed to air. To
prevent the contact of phosphorus with atmospheric
oxygen, it is stored in water.

15. Reaction with Acids
Non Metals generally do not
react with acids.

17. Metals
Metals :- They lose electrons and become positive ions. So they are
called electropositive elements.
E.g. :- 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 Na + + 1 e-
AN = 11
EC = 2,8,1 2,8

18. Non Metals
Non Metals :- They gain electrons and become negative ions. So they are
called electronegative elements.
E.g. :- The atomic number of chlorine is 17, its electronic configuration is
2,8,7, it has 7 valence electron. It gains 1 electron and forms a chlorine
ion Cl -
Cl + 1 e- Cl +
AN = 17
EC = 2,8,7 2,8,8

20. Corrosion is the damage caused to metals due to the reaction of metals with
oxygen, moisture, carbon dioxide etc.
E.g. :- 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.

21. 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)
Alloy :-
An alloy is a homogeneous mixture of a metal with other metals or non metal.
E.g. :- 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.
Prevention of Metals from Corrosion