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

Options

A. `Vn^(2+)ltCr^(2+)ltMn^(2+)ltFe^(2+)`, Paramagnetic behaviour
B. `Ni^(2+)ltCO^(2+)ltFe^(2+)Mn^(2+)` : ionic size
C. `Co^(3+)ltFe^(3+)Cr^(3+)ltSc^(3+)`:Stability in aqueous solution
D. `ScltTiltCrltMn`: number of oxidation states

Answer

1

Explanation

(1) `V^(2+)=3` unpaired electrons
`Cr^(2+)`=4 unpaired electrons
`Mn^(2+)=5` unpaired electrons
`Fe^(2+)=4` unpaired electrons
Hence the order of paramagnetic behaviour should be
`V^(2+)ltCr^(2+)=Fe^(2+)ltMn^(2+)`
(2) ionic size decrease from left to right in same period.
(3) As per data from NCERT.
`CO^(3+)//Co^(2+)=1.97,Fe^(3+)//Fe^(2+)=0.77,Cr^(3+)//Cr^(2+)=-0.41`
`Sc^(3+)` is highly stable (it does not show `+2`)
(4) The oxidation states increases as we go from `3` to group `7` in same period.
Ansis `(1)`