List three properties of sodium in which it differs from the general physical properties of most metals.

How is copper obtained from $Cu_{2}S$? Give reactions.

$A$ solution of $CuSO_{4}$ was kept in an iron pot. After a few days,the iron pot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved.

Give reasons for the following:
$(i)$ Carbon can reduce zinc oxide to zinc but not calcium oxide to calcium.
$(ii)$ Copper and aluminium wires are usually used for electricity transmission.

$(a)$ Why does calcium start floating when added to water?
$(b)$ Most metals do not release hydrogen gas when reacting with nitric acid. Why?
$(c)$ Write the chemical equation for the reaction of iron with steam. Name the compound of iron obtained.

Silver articles become black on prolonged exposure to air. This is due to the formation of