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.
