NEET NEET SOLVED PAPER 2013

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

    A)  \[\text{C}{{\text{e}}^{\text{2+}}}\]

    B) \[\text{S}{{\text{m}}^{\text{2+}}}\]

    C) \[\text{E}{{\text{u}}^{\text{2+}}}\]

    D) \[\text{Y}{{\text{b}}^{\text{2+}}}\]

    Correct Answer: D

    Solution :

    Lanthanide ion with no unpaired electron is diamagnetic in nature. \[C{{e}_{58}}=[Xe]4{{f}^{2}}5{{d}^{0}}6{{s}^{2}}\] \[C{{e}^{2+}}=[Xe]4{{f}^{2}}\] (two unpaired electrons)     \[S{{m}_{62}}=[Xe]4{{f}^{6}}5{{d}^{0}}6{{s}^{2}}\] \[S{{m}^{2+}}=[Xe]4{{f}^{6}}\] (six unpaired electrons) \[E{{u}_{63}}=[Xe]4{{f}^{7}}5{{d}^{0}}6{{s}^{2}}\] \[E{{u}_{63}}=[Xe]4{{f}^{7}}\] (seven unpaired electrons) \[Y{{b}_{70}}=[Xe]4{{f}^{7}}5{{d}^{0}}6{{s}^{2}}\] \[Y{{b}^{2+}}=[Xe]4{{f}^{14}}\] (no unpaired electrons) Because of the absence of unpaired electrons, \[Y{{b}^{2+}}\] is diamagnetic.


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