In the d-block elements, the third-row metallic radii are about the same as the second-row radii because of
A) the lanthanide contraction.
B) the third-row metallic radii are greater than the second-row radii.
C) the increased number of d-electrons.
D) greater shielding of f-electrons.
E) greater shielding of d-electrons.

Question

Quizplus · Accepted Answer

The lanthanide contraction is a phenomenon in which the atomic radii of the elements in the lanthanide series are smaller than predicted due to the increased nuclear charge being partially offset by poor shielding of the 4f electrons. This contraction affects the properties of the d-block elements that follow, resulting in their third-row metallic radii being similar to the second-row radii.

In the D-Block Elements, the Third-Row Metallic Radii Are About