Question

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

• A. $CO ^{+2}< Fe ^{+2}< Mn ^{+2}$ - lonic size
• B. $Ti < V < Mn $ - Number of oxidation states
• C. $Cr ^{+2}< Mn ^{+2}< Fe ^{+2}$ - Paramagnetic behaviour
• D. none of the above

Answer 1

The Correct Option is D

$\underset{24}{ Cr }[ Ar ] 3 d ^{5} 4 s ^{1} \,\,\, Cr ^{2+} 3 d ^{4} 4 s ^{0}=4$ unpaired electrons
$Mn [ Ar ] 3 d ^{5} 4 s ^{2} Mn ^{2+} 3 d ^{5} 4 s ^{0}=5$ unpairedelectrons
$Fe [ Ar ] 3 d ^{6} 4 s ^{2} \,\,\,Fe ^{2+} 3 d ^{6} 4 s ^{0}=4$ unpaired electrons
Since both $Cr ^{2+}$ and $Fe ^{2+}$ contain $4$ unpaired electrons, the correct option is $C$.
Option D is also correct because density order given is not correct.