Which of the following does not represent the correct order of the properties indicated ?

Options

A. `Ni^(2+) gt Cr^(2+) gt Fe^(2+) gt Mn^(2+)` size
B. `Sc gt Ti gt Cr gt Mn` (size)
C. `Mn^(2+) gt Ni^(2+) lt Co^(2+) lt Fe^(2+)` (unpaired electron)
D. `Fe^(2+) gt Co^(2+) Ni^(2+) gt Cu^(2+)` (unpaired electron)

Answer

A

Explanation

In a period on moving from left to right , ionic radii ecreases. Thus
(a) order of cationic radii is
`Cr(2+) gt Mn^(2+) gt Fe^(2+) gt Ni^(2+)`
(b) `Sc gt Ti gt Cr gt Mn`( correct order of atomic radii)
(c) For unpaired electrons
`Mn^(2+)" (Five)" gt Ni^(2+)` (two)
`lt Co^(2+) " (Three) " lt Fe^(2+)` (Four)
(d) For unpaired electrons `gt Fe^(2+) " (Four)" gt Co^(2+) " (Three)" gt Ni^(2+) (two) gt Cu^(2+)(One)`