Two metals $A$ and $B$ having similar ionic radii,react with oxygen to give only monoxides and react with nitrogen to give nitrides. Then,$A$ and $B$ respectively are

Crude sodium chloride obtained by crystallisation of brine solution does not contain

When an alkali metal dissolves in liquid ammonia,the solution can acquire different colours. Explain the reasons for this type of colour change.

Alkali metals react with water to form hydroxides and release hydrogen gas. This is because:

The $s$-block elements are characterised by their larger atomic sizes,lower ionisation enthalpies,invariable $+1$ oxidation state and solubilities of their oxosalts. In the light of these features,describe the nature of their oxides,halides and oxosalts.

Which of the following will be dissolved in excess of $NaOH$?