Atomic radii of the transition elements are smaller than those of the s-block elements because:

Options

A. there is increase in the nuclear 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 begininh, the atomic radius decrease with the increase in nuclear charge (as atomic number increase), whereas the shielding effect of d-electrons is small and orbital electrons are added to the penultimate d-subshell rather than tot he outer shell of the atom.