Which of the following elements can be represented by the electronic configuration $[Kr]\,5s^2$?

Which of the following statement$(s)$ is/are correct?
$(i)$ $LiNO_3$ and $Ba(NO_3)_2$ both will give $NO_2$ on heating.
$(ii)$ $BaSO_4$ is less soluble in water than $CaSO_4$.
$(iii)$ Alkaline earth metals do not dissolve in liquid ammonia.

Consider the following statements:
Statement-$I$: Both $BeSO_4$ and $MgSO_4$ are readily soluble in water.
Statement-$II$: Among the nitrates of alkaline earth metals,only $Be(NO_3)_2$ on strong heating gives its oxide,$NO_2$,and $O_2$.

Magnesia is

Which of the following salts becomes Plaster of Paris on being appropriately heated?

The ‘milk of magnesia’ used as an antacid is chemically