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NEET Sample Paper NEET Sample Test Paper-38

  • question_answer
    For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order?

    A)  Cr > Mn > Co > Fe

    B)  Mn > Fe > Cr > Co

    C)  Fe > Mn > Co > Cr

    D)  Co > Mn > Fe > Cr

    Correct Answer: B

    Solution :

    \[M{{n}^{2+}}({{d}^{5}})\] gets highest stabilization due to half-filled configuration. In case of\[F{{e}^{2+}}({{d}^{6}}),\]addition of one extra electron in the subshell destabilizes it. Addition of two electrons in case of \[C{{o}^{2+}}({{d}^{7}})\]destabilizes it more.\[C{{r}^{2+}}({{d}^{4}})\]has one vacant subshell. Fe24" gets more stabilization as compared to Cr through exchange energy. So correct order is Mn > Fe > Cr > Co.


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