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

Options

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

Explanation

As 5f orbitals extend farther from the nucleus than 4f orbitals, the attraction on the 5f electrons in actinoid series decreases. Hence, they can easily participate in bonding and, therefore, exhibit more number of oxidation states.