Lanthanoid ions with $4 f^7$ configuration are :
(A) $\mathrm{Eu}^{2+}$
(B) $\mathrm{Gd}^{3+}$
(C) $\mathrm{Eu}^{3+}$
(D) $\mathrm{Tb}^{3+}$
(E) $\mathrm{Sm}^{2+}$
Choose the correct answer from the options given below :

Question

Aicharya · Accepted Answer

$\begin{aligned} & { }_{63} \mathrm{Eu}^{2+}-[\mathrm{Xe}] 4 \mathrm{f}^7 6 \mathrm{~s}^0 \ & { }_{64} \mathrm{Gd}^{3+}-[\mathrm{Xe}] 4 \mathrm{f}^7 5 \mathrm{~d}^0 6 \mathrm{~s}^0 \ & { }_{63} \mathrm{Eu}^{3+}-[\mathrm{Xe}] 4 \mathrm{f}^6 6 \mathrm{~s}^0 \ & { }_{65} \mathrm{~Tb}^{3+}-[\mathrm{Xe}] 4 \mathrm{f}^8 6 \mathrm{~s}^0 \ & { }_{62} \mathrm{Sm}^{2+}-[\mathrm{Xe}] 4 \mathrm{f}^6 6 \mathrm{~s}^0 \ & \mathrm{Eu}^{2+} \& \mathrm{Gd}^{3+}\end{aligned}$

Lanthanoid ions with $4 f^7$ configuration are : (A) $\mathrm{Eu}^{2+}$ (B) $\mathrm{Gd}^{3+}$ (C)…

Solution