Question

Two elements X and Y are starting elements of 3rd and 4th periods. Compare their densities and give the reason.

Answer 1

Given, $X$ and $Y$ belong to both $3^{rd}$ and $4^{th}$ period then the increase in volume i.e atomic radii is very high compared to the increase in atomic mass from $3^{rd}$ period to $4^{th}$ period. So, density of $X$ $>$ density of $Y$.