1. Metals: Lithium Beryllium Sodium Magnesium Aluminium Potassium Calcium Scandium Titanium Vanadium . Non metals : Hydrogen Helium Chlorine Fluorine Carbon Nitrogen Oxygen Phosphorous Bromine Iodine.

2. When a metal is burnt in the air, it gets oxidized in the presence of oxygen and forms metal oxide.

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4. (i) Mercury is a liquid at room temperature. (ii) Sodium, potassium can be easily cut with a knife. (iii) Silver and copper are good conductor of heat. (iv) Lead is a poor conductor of heat.

5. Ductility. Malleability. Ductility is the property of metal associated with the ability to be stretched into wire without breaking. Malleability is the property of metal associated with the ability to be hammered into a thin sheet without breaking. The external force or stress is tensile stress.

6. Sodium is high reactive element. If it is kept in open it can explosively react with oxygen to catch fire. Hence to prevent accidental damage sodium is immersed in kerosene oil.

7. Gold, platinum, copper and silver are least reactive metals, hence they are found in the free state in nature.

8. Gold and Platinum are the metals which do not corrode easily. Since they are unaffected by oxygen and other acids, they do not corrode visibly and are more stable than many of their compounds, such as oxides and sulphides.

9. Two ways to prevent the rusting of iron are: Oiling, greasing, or painting: By applying oil, grease, or paint, the surface gets a waterproof coating and the moisture and oxygen cannot come into direct contact with the iron article. Hence, rusting is prevented.

10. Corrosion is the natural process in which the transformation occurs from pure metal to an undesirable substance. This happens because the metals when exposed to air or water will get corroded. The metal will lose shine and colored layer in the presence of air or water, such process is so-called corrosion.

    
    

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