Question

In which of the following lanthanides oxidation state $+2$ is most stable ?

• A. $Ce$
• B. $Eu$
• C. $Tb$
• D. $Dy$

Answer 1

The correct option is B $Eu$

$E{u}^{2+}$ has electronic configuration $\left[Xe\right]4f^7$ hence stable due to half filled atomic orbitals.