Question

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

• A. the 5f orbitals are more buried than the 4f orbitals.
• B. there is a similarity between 4f and 5f orbitals in their angular part of the wave function.
• C. the actinoids are more reactive than the lanthanoids.
• D. the 5f orbitals extend further from the nucleus than the 4f orbitals.

Answer 1

Answer: (D)

Lanthanoids primarily show three oxidation states (+2, +3, +4). Among these oxidation states, +3 state is the most common. Lanthanoids display a limited number of oxidation states because the energy difference between 4f, 5d and 6s orbitals is quite large. On the other hand, the energy difference between 5f, 6d and 7sorbitals is very less. Hence, actinoids display a large number of oxidation states.