Chemistry - f-block Question with Solution | TestHub

$\begin{array}{rl}& {\mathrm{La}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^0\\ & {\mathrm{Nd}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^3\\ & {\mathrm{Sm}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^5\\ & {\mathrm{Eu}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^6\\ & {\mathrm{Lu}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^{14}\end{array}$ ${\mathrm{La}}^{+3}$ and ${\mathrm{Lu}}^{+3}$ do not show any colour because no unpaired electron is present.