question_answer

Which one of the following shows maximum value of paramagnetic behavior?

A)  \[{{[Sc{{(CN)}_{6}}]}^{3-}}\]    

B)  \[{{[Co{{(CN)}_{6}}]}^{3-}}\]

C)  \[{{[Fe{{(CN)}_{6}}]}^{4-}}\]

D)  \[{{[Cr{{(CN)}_{6}}]}^{3-}}\]

Correct Answer: D

Solution :

Key Idea: Calculate the oxidation state of central metal ion as that gives idea of about number of unpaired or paired electrons. \[{{[Sc{{(CN)}_{6}}]}^{3-}}\] \[Sc=21=1{{s}^{2}},{{\,}^{2}}{{s}^{2}},{{\,}^{2}}{{p}^{6}},{{\,}^{3}}{{s}^{2}},3{{p}^{6}},{{\,}^{4}}{{s}^{2}},{{\,}^{3}}{{d}^{1}}\]                                 \[Ni(CN)_{4}^{2-}\]                 No unpaired electron hence, diamagnetic \[{{[Co{{(CN)}_{6}}]}^{3-}}\] \[{{[Cr{{(CN)}_{6}}]}^{3-}}\]