explain why ce+3 can be easily oxidized to ce+4?

Cerium has electronic configuration: Xe 4f¹ 5d¹ 6s²

Ce³⁺ = Xe 4f¹

which is easily converted to the Ce⁴⁺. As after loosing one more electron it will convert to the stable empty electronic configuration.

Ce³⁺ = Xe 4f⁰

therefore it is easily converted to Ce+4

Ce4 + Redox System Following the findings of Mino and Kaizerman [51] that eerie ion can form a redox system with cellulose, ... and (ii)] shift toward more and more of Ce4+ and [Ce(OH)3]3 + , which easily form complexes with functional groups of wool. ... The graft yield was explained in terms of basicity, nu- cleophilicity, and steric requirements of amines. ... chelates containing transition metals in their higher oxidation states are known to decompose by one electron transfer process