Question

Which of the following lanthanoid ions is diamagnetic?
(At nos. Ce = 58, Sm = 62, Eu = 63, Yb = 70)

• A. $Sm^{2 +}$
• B. $Eu^{2 +}$
• C. $Yb^{2 +}$
• D. $Ce^{2 +}$

Answer 1

Answer: (C)

$\text{Yb} = \left[\text{Xe}\right]^{54} 4 \text{f}^{14} 5 \text{d}^{0} 6 \text{s}^{2}$
$Yb^{2 +}=\left[\right.Xe\left]\right.4f^{14}$
As n = 0 so diamagnetic.
As in rest other there are unpaired electron/s so they are paramagnetic.