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

Options

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

Answer

B