Question

Name a member of lanthanoid series which is well known to exhibit $+2$ oxidation state.

Answer 1

Eurpium and Yetterbium having atomic no's 63 and 70 respectively shows +2 oxidation states since their electronic configurations are:

Eu $\to$ [Xn] 4f${}^{7}6s^2$

Yb $\to$ [Xn] 4f${}^{14}6s^2$

So, after removal of 2e${}^{-}$ s , half and fully filled configurations are attained. So, they show +2 oxidation states.