Question

Which of the following lanthanoid ions is diamagnetic ?
(Atoms, Ce = 58, Sm = 62, Yb = 70)

• A. $Y{b}^{2+}$
• B. $E{u}^{2+}$
• C. $C{e}^{2+}$
• D. $S{m}^{2+}$

Answer 1

The correct option is A $Y{b}^{2+}$

Lanthanide ion with no unpaired electron is diamagnetic in nature.
Electronic configuration:
$Y{b}^{2+}:\left[Xe\right]4f^{14}$
Diamagnetic, since no unpaired electron
$C{e}^{2+}:\left[Xe\right]4f^2$
Paramagnetic, since 2 unpaired electrons
$S{m}^{2+}:\left[Xe\right]4f^6$
Paramagnetic, since 6 unpaired electrons
$E{u}^{2+}:\left[Xe\right]4f^7$
Paramagnetic, since 7 unpaired electrons
Option (a) is correct