question_answer

Number of unpaired electrons in \[M{{n}^{4+}}\] is :

A)  3               

B)  5

C)  6               

D)  4

Correct Answer: A

Solution :

Key Idea: Write the electronic configuration of Mn in ground state then \[M{{n}^{4+}}\]. Draw the orbitals to find unpaired electrons. Mn- (At. no. = 25) \[=1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{2}}3{{d}^{5}}\] \[\therefore \,\,\,M{{n}^{4+}}1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},4{{s}^{0}},3{{d}^{3}}\] \[\therefore \,\,M{{n}^{4+}}\] has three unpaired electrons.