Question

More number of oxidation states are exhibited by the actinoids than by lanthanoids. The main reason for this is:

• A. greater metallic character of the lanthanoids than that of the corresponding actinoids.
• B. more active nature of the actinoids.
• C. more energy difference $5f$ and $6d$-orbitals than that between $4f$ and $5d$-orbitals.
• D. lesser energy difference between $5f$ and $6d$-orbitals than that between $4f$ and $5d$-orbitals.

Answer 1

The correct option is D lesser energy difference between $5f$ and $6d$-orbitals than that between $4f$ and $5d$-orbitals.

Actinoids display more oxidation states because of very small energy gap between 5f, 6d and 7s sub shells. Thus, the outermost electrons get easily excited to the higher energy level giving variable oxidation state.

Hence,option D is correct.