\({\left[ Cr ^{+3}\right]=4 s ^{0} 3 d ^{3} }\)
\(\mu=\sqrt{ n ( n +2)}\,B.M\)
\(=\sqrt{15}\) B.M \(\sim 4\,B.M\)
(આપેલ પરમાણુ ક્રમાંક : $Sc : 21, Тi : 22, V : 23, Cr : 24, Mn : 25, Fe : 26, Co : 27,$ $\mathrm{Ni}: 28, \mathrm{Cu}: 29, \mathrm{Zn}: 30)$