Question

Justify the following with suitable reasons: Size of the atom increases as we move down the group.

Answer 1

As we move down in a group a new shell (quantum number n) is added for each consecutive element. There is an equivalent increase in number of protons as well, however the farthest electrons do not experience as much nuclear pull due to electron shielding of inner shells. Therefore the valence electrons are loosely held. It increases the overall atomic size.