Answer the following
Cerium and Terbium behave as good oxidising agents in the +4 oxidation state. Explain.
i. Cerium (Ce) and Terbium (Tb) show +4 oxidation states. Their electronic configurations are given below:
Ce = [Xe] 4f1 5d1 6s2 ; Ce4+ = [Xe]
Tb = [Xe] 4f9 6s2 ; Tb4+ = [Xe] 4f7
ii. It is clear from the configuration of Ce that Ce4+ is favoured by its noble gas configuration. But it can be easily converted into stable Ce3+ by a gain of an electron. Due to this reason, Ce4+ is a good oxidizing agent.
iii. Similarly, Tb4+ ion is stabilized due to a half-filled f-subshell. It can be easily converted into stable Tb3+ by gain of an electron. Due to this reason, Tb4+ is a good oxidizing agent.