Which of the following ions is diamagnetic ?

Ti4+ has the configuration 0 0 3d 4s . This means that there are no unpaired electrons in Ti4+. Thus the absence of unpaired electrons makes it diamagnetic. Ni2+has the configuration 8 0 3d 4s , it has 2 unpaired electrons, while Cr3+has the configuration 3 0 3d 4s , it has 3 unpaired electrons and Co3+has the configuration 6 0 3d 4s , it has 4 unpaired electrons. Hence, all of them are paramagnetic and only Ti4+is diamagnetic. 20. Number of unpaired electrons in Mn3+ is (a) 2 (b) 3 (c) 4 (d) 5 The ground state elect