Which of the following arrangements does not represent the correct order of the property stated

1. V2+<Cr2+<Mn2+<Fe2+: paramagnetic behaviour

2. Ni2+<Co2+<Fe2+<Mn2+ : ionic size

3. o3+<Fe3+<Cr3+<Sc3+ : stability in aqueous solution

4. Sc < Ti < Cr Mn . number of oxidation states

Answer:

(a) V2+ = 3 unpaired electrons

Cr2+ = 4 unpaired electrons

Mn2+ = 5 unpaired electrons

Fe2+ = 4 unpaired electrons

Hence, the order of paramagnetic behaviour should be

V2+<Cr2+=Fe2+<Mn2+

(b) Ionic size decreases from left to right in the same period

.(c)

Co3+/Co2+=1.97;

Fe3+/Fe2+=0.77;

Cr3+/Cr2+=−0.41;

Sc3+ is highly stable (It does not show + 2).

(d) The oxidation states increases as we go from group 3 to group 7 in the same period.