Question

Name of the members of the lanthanoid series which exhibit +4 oxidation state. Try to correlate this type of behaviour with the electronic configuration of these elements.

Answer 1

+4: Ce(Z=58), Pr(Z=59), Nd(Z=60), Tb(Z=65), Dy(Z = 66)

+2: Nd(Z = 60); Sm(Z = 62); Eu(Z = 63), Tm(Z = 69); Yb(Z = 70)

+2 Oxidation state is exhibited when lanthanoid has the configuration 5d⁰ 6s². So that 2 electrons one easily lost. +4 state is exhibited when the electronic configuration left to close to 4f⁰ (eg: 4f⁰, 4f¹, 4f²) or close to 4f⁷ (eg: 4f⁷ or 4f⁸)