Which of the following arrangements does not represent the correct order of the property stated against it? a)N i 2 + < C o 2 + < F e 2 + < M n 2 + : Ionic size b)C o 3 + < F e 3 + < C r 3 + < S c 3 + Stability in aqueous solution c)Sc < Ti < Cr < Mn: Number of oxidation states d)V 2 + < C r 2 + < M n 2 + < Fe^(2+)`: Paramagnetic behaviour

Options

A. `Ni^(2+) lt Co^(2+) lt Fe^(2+) lt Mn^(2+)`: Ionic size
B. `Co^(3+) lt Fe^(3+) lt Cr^(3+) lt Sc^(3+)` Stability in aqueous solution
C. Sc `lt `Ti `lt `Cr Mn: Number of oxidation states
D. `V^(2+) lt Cr^(2+) lt Mn^(2+) Fe^(2+)`: Paramagnetic behaviour

Answer

D

Explanation

`Fe^(2+)` + contains four unpaired electrons as `Cr^(2+)`, whereas `Mn(2+)`contains five unpaired electrons. The correct order should be `V^(2 +) lt Cr^(2+) = Fe^(2+) lt Mn^(2+)`