Mg2+ = 10 = 1s2, 2s2, 2p6 number of unpaired electrons = 0
Ti3+ = 19 = 1s2, 2s2, 2p6, 3s2, 3p6, 4s0, 3d1 number of unpaired electrons =1
Fe2+ = 24 = 1s2, 2s2, 2p6, 3s2, 3p6, 4s0, 3d6 number of unpaired electrons =4
Mn2+ = 23 = 1s2, 2s2, 2p6, 3s2, 3p6, 4s0, 3d5 number of unpaired electrons =5 maximum number
Answer:(d)