The main reason for larger number of oxidation state exhibited by the actinides than the corresponding lanthanides, is

Options

A. lesser energy difference between `5f` and `6d` orbitals than between `4f` and `5d`-orbitals
B. larger atomic size of actinides than the lanthanides
C. more energy difference between `5f` and `6d` orbitals than between `4f` and `5d`-orbitals
D. greater reactive nature of the actinides than the lanthanides

Answer

A

Explanation

A both `5f` and `4f` orbitals have similar shapes and they resemble in their angular part of the wave functions. But `4f` orbitals is much more penetrated than `5f` orbital towards nucles.