Following are the transition metal ions of3d series : Ti^(4+),V^(2+), Mn^(3+), Cr^(3+) (Atomci number : Ti = 22, V = 23 , Mn = 25 , Cr = 24) Anser the following : (i) Which ion is most stable in aqueous solution and why ? (ii) Whichion is a strong oxidizing agent and why ? (iii) Which ion is colourless and why ?

Following are the transition metal ions of3d series : Ti^(4+),V^(2+),

1.	Following are the transition metal ions of3d series : Ti^(4+),V^(2+), Mn^(3+), Cr^(3+) (Atomci number : Ti = 22, V = 23 , Mn = 25 , Cr = 24) Anser the following : (i) Which ion is most stable in aqueous solution and why ? (ii) Whichion is a strong oxidizing agent and why ? (iii) Which ion is colourless and why ?
Answer» Solution :(i) Their electronic configuration are `:` `Ti^(4+)= 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6)` `V^(2+) =1s^(1)2s^(2)2p^(6) 3s^(2) 3p^(6) 3d^(3)` `Cr^(3+) = 1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(3)` `Mn^(3+) =1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(4)` Thus , `Ti ^(4+)` is the most STABLE because it has noble gas configuration. (ii) Oxidizing agent is the substance which itself is reduce most easily, i.e., can gain ELECTRON easily. `V^(2+)` and `Cr^(3+)` are also stablebecause they have filled `t_(2g)` level (i.e., `t_(2g)^(3))` discussed in unit 9. Thus, `Mn^(3+)` can gain electron easily. Moreover `Mn^(2+)` is more stable than `Mn^(3+)` . Hence, `Mn^(3+)` is the strongest oxidizing agent. (iii) Ions are COLOURED if they have incompletely filled d-orbitals. Those with fully - filled or empty d-orbitals are coloureless . As` Ti^(4+)` has empty d-orbitals, hence it is colourless.