One among the lanthanoides, `Ce(III)`, can be easily oxidized to Ce(IV) (At.No. of ce=58) explain why?

Answer

`Ce(III)` having the configuration `4f^(1)5d^(0)6s^(0)` can easily lose an electron to acquire the configuration `4f^(0)` and from `Ce(IV)` in , fact this is the only `(+IV)` lanthanoide which exists in solution.