Calculate the number of unpaired electrons in the following gaseous ions : `Mn^(3+), Cr^(3+), V^(3+)` and `Ti^(3+)`. Which one of these is the most stable in aquenous solution ?

Explanation

`{:("Ion with atomic","Outer electronic","No. of unpaired"),(" number"," configuration"," electrons"),(Mn^(3+)(Z=25)," "3d^(4)," "4),(Cr^(3+)(Z=24)," "3d^(3)," "3),(V^(3+)(Z=23)," "3d^(2)," "2),(Ti^(3+)(Z=22)," "3d^(1)," "1):}`
In aqueous solution `Cr^(3+)` ion is most stable, because it has half - filled `t_(2g)` level (i.e., `t_(2g)^(3)` configuration).