Although `+3` is the characteristic oxidation state for lanthanoids but cerium also shows `+4` oxidation state because

Options

A. it has variable ionisation enthalpy
B. it has a tendency to attain noble gas configuration
C. it has a tendency to attain `f^(0)` configuration
D. it resembles `Pb^(4+)`

Answer

B, C

Explanation

Electronic configuration of `._(58)Ce = ._(54)[Xe]4f^(2)5d^(0)6s^(2)`.
Therefore, electronic configuration of `Ce^(4+)=._(54)[Xe]4f^(0)`.
Thus, it has a tendency to attain noble gas configuration and attain `f^(0)` configuration.