Chemistry - f-block Question with Solution | TestHub

Electronic configuration of $\mathrm{Ce}=\left[\mathrm{Xe}\right]\underset{}{\underbrace{4{\mathrm{f}}^{1}5{\mathrm{d}}^{1}6{\mathrm{s}}^2}}\stackrel{-4{\mathrm{e}}^{-}}{\to }\underset{}{\underbrace{\left[\mathrm{Xe}\right]}}$

Cerium in $+4$ oxidation state due to stable xenon configuration. $\mathrm{La}, \mathrm{Lu} \mathrm{and} \mathrm{Gd}$ are stable in +3 oxidation state.