Question

Name the members of the lanthanoid series which exhibit $+4$ oxidation states and those which exhibit $+2$ oxidation states. Try to correlate this type of behaviour with the electronic configurations of these elements.

Answer 1

$\text{Members of the lanthanoid which exhibit}+2\text{and}+4\text{oxidation states}$

The members of the lanthanoid series which exhibit $+2$ and$+4$ oxidation states are shown below in table:

$\begin{array}{cc}(+2)\text{Oxidation state}& (+4)\text{Oxidation state}\\ Nd\left(60\right)& Ce\left(58\right)\\ Sm\left(62\right)& Pr\left(59\right)\\ Eu\left(63\right)& Nd\left(60\right)\\ Tm\left(69\right)& Tb\left(65\right)\\ Yb\left(70\right)& Dy\left(66\right)\end{array}$

$\text{Correlate with the electronic configurations}$

General electronic configuration of lanthanoid series can be written as:

$\left[Xe\right]4f^{1-14}5d^{0-1}6s^2$

Since we know, half-filled and completely filled orbitals are highly stable.

$\text{Tb}$ after forming $T{b}^{4+}$ attains $a$ stable

electronic configuration of $\left[Xe\right]4f^7.$

$\text{Eu}$ after forming $E{u}^{2+}$ attains a stable

electronic configuration of $\left[Xe\right]4f^7.$

$\text{Yb}$ after forming $Y{b}^{2+}$ attains a stable

electronic configuration of $\left[Xe\right]4f^{14}.$

$\text{Ce}$ after forming $C{e}^{4+}$ attains a stable

electronic configuration of $\left[\text{Xe}\right].$