Question

The chemistry of the actinoids is more complex as compared to the lanthanoids. Why?

Hint:

Actinoid contraction is more irregular; variable oxidation states and stronger 5f participation lead to complex behavior.

Answer 1

Step 1: In actinoids, 5f orbitals participate in bonding, while in lanthanoids, 4f orbitals are deeply buried and less involved.
Step 2: Actinoids show variable oxidation states ranging from +3 to +6 (sometimes +7), whereas lanthanoids predominantly show +3 oxidation state.
Step 3: The 5f electrons in actinoids are more shielded and more easily influenced by ligands.