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 aqueous solution?

Answer 1

| Gaseous ions| Number of unpaired electrons
---|---|---
(i)| Mn3+, [Ar]3d4| 4
(ii)| Cr3+, [Ar]3d3| 3
(iii)| V3+, [Ar]3d2| 2
(iv)| Ti3+, [Ar]3d1| 1

Cr3+ is the most stable in aqueous solutions owing to a $t^3_{2g}$ configuration