Question

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

• A. $C{O}^{+2}<F{e}^{+2}<M{n}^{+2}$ - lonic size
• B. $Ti<V<Mn$ - Number of oxidation states
• C. $C{r}^{+2}<M{n}^{+2}<F{e}^{+2}$ - Paramagnetic behaviour
• D. none of the above

Answer 1

Answer: (C)

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