Neet Solved Paper 2013 Question 22

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

Options:

A) $ C{e^{\text{2+}}} $

B) $ S{m^{\text{2+}}} $

C) $ E{u^{\text{2+}}} $

D) $ Y{b^{\text{2+}}} $

Show Answer

Answer:

Correct Answer: D

Solution:

  • Lanthanide ion with no unpaired electron is diamagnetic in nature.
    $ Ce _{58}=[Xe]4f^{2}5d^{0}6s^{2} $ $ C{e^{2+}}=[Xe]4f^{2} $ (two unpaired electrons)
    $ Sm _{62}=[Xe]4f^{6}5d^{0}6s^{2} $ $ S{m^{2+}}=[Xe]4f^{6} $ (six unpaired electrons)
    $ Eu _{63}=[Xe]4f^{7}5d^{0}6s^{2} $ $ Eu _{63}=[Xe]4f^{7} $ (seven unpaired electrons)
    $ Yb _{70}=[Xe]4f^{7}5d^{0}6s^{2} $ $ Y{b^{2+}}=[Xe]4f^{14} $ (no unpaired electrons)

Because of the absence of unpaired electrons, $ Y{b^{2+}} $ is diamagnetic.