Question

Larger number of oxidation states are exhibited by the actinoids then those by the lanthanoids, the main reason being
A. 4f orbitals are more diffused than the 5f orbitals
B. lesser energy difference between 5f and 6d than between 4f and 5d orbitals
C. more energy difference between 5 f and 6d than between 4f and 5d orbitals
D. more reactive nature of the actinoids than the lanthanoids

Answer 1

Correct Answer - B
Lanthanoids `[Xe]4f^(1-14)5d^(0-1)6s^(2)`
Actinoids `[Rn]5f^(1-14)6d^(0-1)7s^(2)`
Lanthanoids and actinoids use core d and f-orbitals also to show higher oxidation state. As actinolds have comparatively low energy difference between f and d-orbitals, thus show more oxidation states.