question_answer

Which of the following has more unpaired d-electrons?                               [AIPMT 1999]

A)  \[Z{{n}^{+}}\]                      

B)       \[F{{e}^{2+}}\]

C)  \[~{{N}^{3+}}\]                    D)       \[C{{u}^{+}}\] Correct Answer: B Solution : \[Zn_{(At.\,No.\,=30)}^{+}=1{{s}^{2}},\,2{{s}^{2}}2{{p}^{6}},\,3{{s}^{2}}3{{p}^{6}}3{{d}^{10}},\,4{{s}^{1}}\]

\[Fe_{(At.\,No.\,26)}^{2+}=1{{s}^{2}},\,2{{s}^{2}}2{{p}^{6}},\,3{{s}^{2}}3{{p}^{6}}3{{d}^{6}}\]

\[N_{(At.\,No.=7)}^{3+}=1{{s}^{2}},2{{s}^{2}}\,2{{p}^{0}}\]

\[Cu_{(At.\,No=29)}^{+}=1{{s}^{2}},2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}\]

So, maximum number of unpaired electrons are present in Fe2+.