JEE Main 2022 — s Block Elements Question with Solution

The size of alkali metals increases down the group, so volume also shows increment, and since volume is inversely proportional to the density but in the case $\mathrm{Sr}$and $\mathrm{Ba}$, increase in the volume is less compared to increasing mass.

So, down the group density decreases first and then increases.

Therefore, the correct order of density is as follows:

'$\mathrm{Ca}<\mathrm{Mg}<\mathrm{Be}<\mathrm{Sr}$