8.8: Calculate the ‘spin only’ magnetic moment of M2+(aq)(aq) ion (Z = 27) 

Z = 27
[Ar] 3d7 4s2
M2+=Ar 3d7
3d7=      
i.e., 3 unpaired electrons
n=3
n(n+2)=μ
3(3+2)=μ
15=μ
μ4 BM