1. By – Miss Kiran Rathod

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 + O 2 2CuO When aluminium is heated it combines with oxygen to form aluminium oxide. 4Al + 3O 2 2Al 2 O 3

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

9. Reaction with Acids Metals react with dilute acids to form salts and hydrogen. Mg + 2HCl MgCl 2 + H 2 2Al + 6HCl 2AlCl 3 + 3H 2 Zn + 2HCl ZnCl 2 + H 2 Fe + 2HCl FeCl 2 + H 2

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 + CuSO 4 MgSO 4 + Cu Zinc displaces copper from copper sulphate solution. Zn + CuSO 4 ZnSO 4 + Cu Iron displaces copper from copper sulphate solution Fe + CuSO 4 FeSO 4 + 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 + O 2 SO 2 When carbon is heated it combines with oxygen to form carbon dioxide. C + O 2 CO 2

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