The actinoids exhibit more number of oxidation states in general than the lanthanoids. This is because

Options

A. the 5f orbital extend farther from the nucleus than the 4f orbitals
B. the 5f orbitalare more buried than the 4f orbital
C. there is a similarity between 4f and 5f orbitals in their angular part of the wave functions
D. The actinoids are more reactive thean the lanthanoids.

Answer

D

Explanation

In the electron orbitals involved in actinoid family (5d,6f and 7s) the energy difference is less as compared to orbitals (5f, 4d and 6s) involved in the lanthanoid family. As a result more electrons becomes available for bond formation in the actinoid family as compared to lanthanoid family, Therefore, the elements belonging to actinoid family exhibited more variable oxidation states as compared to those belonging to lanthanoid family.