An element X is trivalent. Write the balanced equation for the combustion of X in oxygen.

The formula of the nitride of a metal X is XN, state the formula of :

(i) it's sulphate (ii) it's hydroxide.

What is meant by the term 'symbol'. Give the qualitative and quantitative meaning of the term 'symbol'.

Name three metals whose symbols are derived from :

(a) the first letter of the name of the element

(b) from their Latin names.