When sodium $(Na)$ metal is dissolved in liquid ammonia $(NH_3)$,it imparts a blue colour to the solution. This blue coloration is due to:

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.

Lithium resembles magnesium in some of its properties. Mention two such properties and give reasons for this resemblance.

Metallic magnesium is prepared by

Nitrates of all metals are:

The melting point of a mixture of $Na_2CO_3 + K_2CO_3$ is: