Oxide of a non-metal possesses the following characteristics
(i) It is both a proton donor and an acceptor
(ii) It is a poor conductor of electricity
(iii) It reacts readily with basic and acides
(iv) It oxidises Fe at its boiling point.This oxide is

Give an example of a metal in each of the following cases : (i) It is preserved in kerosene. (ii) It is the poorest conductor of electricity. (iii) It is the best conductor of electricity . (iv) It lies at the top of the reactivity series.

Give reasons for the following : (i) Metals are good conductors of electricity whereas non-metals are not. (ii) Ionic compounds have usually high melting and boiling points.

Name the non-metals which show the following properties : (i) A non-metal which has lustre and is a good conductor of electricity. (ii) A non-metal which is the hardest natural substance. (iii) A non-metal which is essential for respiration (iv) A non-metal which is the source of energy in the sun and stars.

Classify the solid that has the given characteristics: (i) very hard, brittle (ii) very high melting point and heat of fusion (iii) non-conductor of electricity and heat in solid state.

Write one example each of : (i) a metal having low melting point and a metal having high melting point. (ii) a metal which is a poor conductor of electricity and a non-metal which is a good conductor of electricity.