Atoms of the transition elements are smaller than those of the s-block elements, because:

Options

A. Threre is increase in the cuclear charge along the period
B. orbital electrons are added to the penultimate d-subshell rather than to the outer shell of the atom
C. the shielding effect of d-electrons is small.
D. All of these.

Answer

D

Explanation

The atomic radii of the transition metals lie in-between those of s- and p-block elements. In the beginning, the atomic radius decreases with the increase in nuclear charge (as atomic number increases), whereas the dhielding effect of d-electronic is small and orbital electrons are added to the penultimate d-subshell rather than to the outer shell of the atom.