Sponsor Area

The D-And-f-Block Elements

Question
CBSEENCH12011127

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

  • Ce2+

  • Sm2+

  • Eu2+

  • Yb2+

Solution

D.

Yb2+

Lanthanoid ion with no unpaired electron is diamagnetic in nature.
Ce58 = [Xe]4f2 5d0 6s2
Ce2+ = [Xe]4f2 (two unpaired electrons)
Sm62 =  [Xe]4f6 5d0 6s2
Sm2+ = [Xe] 4f6 (six unpaired electron)

Eu63 =  [Xe]4f7 5d0 6s2
Eu2+ = [Xe] 4f7 (seven unpaired electron)

Yb70 =  [Xe]4f14 5d0 6s2
Yb2+ = [Xe] 4f14 (No unpaired electron)
Because of the absence of unpaired electrons, Yb2+ is diamagnetic.