The lightest metal is

The metal that forms nitride by reacting directly with $N_2$ of air is

Arrange the following compounds in the increasing order of their thermal stability. Identify the correct sequence.
$I - K_2CO_3, II - MgCO_3, III - CaCO_3, IV - BeCO_3$

Identify the correct statements about alkali metals.
$A$. The order of standard reduction potential $(M^{+} \mid M)$ for alkali metal ions is $Na > Rb > Li$.
$B$. $CsI$ is highly soluble in water.
$C$. Lithium carbonate is highly stable to heat.
$D$. Potassium dissolved in concentrated liquid ammonia is blue in colour and paramagnetic.
$E$. All the alkali metal hydrides are ionic solids.
Choose the correct answer from the options given below.

Which of the following statements is correct regarding the solubility of carbonates?

What is the chemical formula of Chile saltpeter?