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

How is calcium sulphate obtained?

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.

Which of the following carbonates undergoes decomposition upon heating?

When the ash obtained by burning a metal in air is moistened,it gives the smell of $NH_3$. Which metal is it?

The property of the alkaline earth metals that increases with their atomic number is