Solution:
The above statement is true.Atomic radius is the distance from the centre of the nucleus to the outermost shell of electrons in an atom. On moving down a group, a new shell of electrons is added to each succeeding element. Hence, the electrons in the valence shell of each succeeding element lie farther and farther away from the nucleus. So, the attraction of the nucleus for the electrons decreases and as a result, the atomic radius increases with an increase in the atomic number. But this increases the nuclear charge of elements. This produces a contractive effect on the atomic radius. The increase in the atomic radius due to the addition of new shells is so large that it outweighs the contractive effect of the increased nuclear charge. As a result, the atomic radius increases on moving down a group from top to bottom.
