Question

Which of the following lanthanoid ions is diamagnetic ? (At. No. $Ce=58,Sm=62,Eu=63,Yb=70$)

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

Answer 1

Answer: (D)

$Y{b}^{2+}$

$\left(A\right)$ $Ce\left[Xe\right]4f^{1}5d^{1}6s^2$

$C{e}^{+2}\left[Xe\right]4f^{1}5d^1$

$2$ unpaired Electron so paramagnetic.

$\left(B\right)$ $Sm\left[Xe\right]4f^{6}6s^2$

$C{e}^{+2}\left[Xe\right]4f^6$

$6$ unpaired Electron so paramagnetic.

$\left(C\right)$ $Ce\left[Xe\right]4f^{7}6s^2$

$C{e}^{+2}\left[Xe\right]4f^7$

$7$ unpaired Electron so paramagnetic.

$\left(D\right)$ $Ce\left[Xe\right]4f^{14}6s^2$

$C{e}^{+2}\left[Xe\right]4f^{14}$

$0$ unpaired Electron so diamagnetic.