ABC26IN0169 · Lanthanides and Actinides

Subject: Inorganic Chemistry · Chapter: Lanthanides and Actinides · Topic: Lanthanides & Actinides – General · Exam: CSIR-NET JUNE 2011 · Marks: 2 · Difficulty: Medium

The electronic configuration for gadalonium $(\mathrm{Gd})$ is $\mathrm{[Xe]4f^{7}\,5d^{1}6s^{2}}$, where as that of $\mathrm{Gd^{2+}}$ is:
(a)$[\mathrm{Xe}] 4 \mathrm{f}^{5} 5 \mathrm{d} 6 \mathrm{s}^{2}$
(b)$[\mathrm{Xe}] 4 \mathrm{f}^{6} \mathrm{6s}^{2}$
(c)$[\mathrm{Xe}] \mathrm{f}^{6} 5 \mathrm{d}^{1} 6 \mathrm{s}^{1}$
(d)$[\mathrm{Xe}] 4 f^{7} 5 d^{1}$
Answer
Answer (as printed): D
Explanation
$_{64}^{157}\mathrm{Gd} = [\mathrm{Xe}]4f^{7}5d^{1}6s^{2}$, $\mathrm{Gd^{2+}}=[\mathrm{Xe}]4f^{7}5d^{1}6s^{0}$. Removal of electrons takes place from the outermost orbital only.

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