Which of the following transition metal ions has a spin-only magnetic moment of 5.92 B.M. ?

Step-by-step solution

The spin-only magnetic moment ( ) is calculated using the formula = n(n+2) B.M. , where n is the number of unpaired electrons. Given = 5.92 B.M. n(n+2) = 5.92 n(n+2) 35 This indicates that the ion must have n = 5 unpaired electrons. Let us evaluate the electronic configurations of the given ions: Mn ²⁺ (Z=25) : [ Ar ] 3d^5 ( 5 unpaired electrons) Fe ²⁺ (Z=26) : [ Ar ] 3d^6 ( 4 unpaired electrons) Cr ³⁺ (Z=24) : [ Ar ] 3d^3 ( 3 unpaired electrons) Ni ²⁺ (Z=28) : [ Ar ] 3d^8 ( 2 unpaired electrons) Thus, Mn ²⁺ is the