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Question
Calculate the number of unpaired electrons in the following gaseous ions:
Mn3+, Cr3+, V3+ and Ti3+. Which one of these is the most stable in an aqueous solution?
Solution
| Gaseous ions | Electronic configurations | Number of unpaired electrons |
| (1) Mn3+ | 3d44s0 | 4 |
| (2) Cr3+ | 3d34s0 | 3 |
| (3) V3+ | 3d24s0 | 2 |
| (4) Ti3+ | 3d14s0 | 1 |
Of these, Cr3+ is most stable in aqueous solution because it has a half-filled t2g level.
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