InterviewSolution
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InterviewSolution
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Which one of the following ions exhibits d-d transition and paramagnetism as well ?A. `MnO_(4)^(-)`B. `Cr_(2)O_(7)^(2-)`C. `CrO_(4)^(2-)`D. `MnO_(4)^(2-)` |
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Answer» Correct Answer - D Key Concept In d-d transition, an electron in a d-orbital of the metal is exicted by a photon to another d-orbital of higher energy. Paramagnetism The complex compound which contains unpaired electrons shows paramagnetism while which contains paired electrons shows diamagnetism. The complex which contains unpaired electrons exhibit d-d transition and paramagnetism. (i) In `MnO_(4)^(-)`, The electronic configuration of `Mn^(7+)` is `[Ar]3d^(0)`. Number of unpaired electrons =0 Therefore, it will be diamagnetic and will not show d-d transition. (ii) In `Cr_(2)O_(7)^(2-)`, The electronic configuration of `Cr^(6+) " is" [Ar]3d^(0)`. Number of unpaired electrons=0 So, it will be diamagnetic and will not show d-d transition. (iii) In `CrO_(4)^(2-)`, The electronic configuration of `Cr^(6+) " is "[Ar]3d^(0)`. Number of unpaired electrons=0 Therefore, it is also diamagnetic and will not show d-d transition. (iv) In `MnO_(4)^(2-)`, The electronic configuration of `Mn^(6+)` is `[Ar]3d^(0)`. Number of unpaired electrons=1 Since, it contains one unpaired electron so it will exhibit both d-d transition and paramagnetism. |
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