Chemistry - f-block Question with Solution | TestHub

${\mathrm{La}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^0$

${\mathrm{Nd}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^3$

${\mathrm{Sm}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^5$

${\mathrm{Eu}}^{+3}-[\mathrm{Xe}]4{\mathrm{f}}^6$

${\mathrm{Lu}}^{+3}-[\mathrm{Xe}]4f^{14}$

${\mathrm{La}}^{+3}$ and ${\mathrm{Lu}}^{+3}$ do not show any colour because no unpaired electron is present.