Magnesium does not decompose which of the following?

Identify correct statements from the following:
$i$. Beryllium oxide is an amphoteric oxide.
$ii$. Group $II$ elements dissolve in liquid ammonia to form deep blue-black solutions.
$iii$. The hydration enthalpy of group $II$ ions decreases from $Be^{2+}$ to $Ba^{2+}$.

Give a brief note on the oxides of alkaline earth metal elements.

$A$ metal is burnt in air and the ash on moistening smells of $NH_3$. The metal is

The correct order of density for the alkaline earth metals is:

Discuss the general characteristics and gradation in properties of alkaline earth metals.