Magnetic moment 2.83 BM is given by which of the following ions?(At.nos. Ti = 22, Cr = 24, Mn = 25, Ni = 28)

Magnetic moment is given by μ=n(n+2)B.M where  n =   no. of unpaired electrons  When n=2 , then μ=2.83 B.M.  For Ti3+3d1,n=1;Cr3+3d3,n=3;Ni2+3d8                                  n=2;Mn2+3d5,n=5Hence, Ni2+has two unpaired electrons, with magnetic moment 2.83 B.M.