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

1.  It has variable ionisation enthalpy

2.  It has a tendency to attain noble gas configuration

3.  It has a tendency to attain f0 configuration

4.  It resembles Pb4+

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

Electronic configuration of C58e = Xe54 4f25d06s2
Therefore, electronic configuration of Ce4+ = Xe544f0
Thus, it has tendency to attain noble gas configuration and attain  f0  configuration.