Compare the chemistry of actinoids with that of the lanthanoids with special reference to :
Oxidation state

Explanation

Oxidation state : Lanthanoids show limited number of oxidation states (+2, +3 and +4), because the energy gap between 4f and 5d - subshell is large. The f - electrons are present in the deeper (n - 2) f - subshell (i.e., 4f-subshell) which can not participate in bond formation. The most common oxidation state is + 3. Actinoids exhibit a large number of oxidation states (+3 to + 7) because, 5f, 6d and 7s - orbitals have comparable energies. It is to be noted that 5f - orbitals are not as buried as 4s - orbitals and hence, 5f - electrons can participate in bonding to a far greater extent. However, the most common oxidation state is + 3.