Question

Select the coloured and paramagnetic ions

• A. $Cu ^{+}, Zn ^{2+}, Cd ^{2+}$
• B. $Sc ^{3+}, Ti ^{4+}, V ^{5+}$
• C. $Cu ^{2+}, Cr ^{+}, Mn ^{2 \mid}$
• D. $Ni ^{2+}, Cu ^{+}, Hg ^{2+}$

Answer 1

Answer: (C)

Ion is coloured if there are unpaired electrons in $d$-suborbit
Paramagnetic nature is also due to unpaired electrons
Thus, every coloured ion is also paramagnetic
$Cu ^{2+}=[ Ar ] 3 d^9$ one unpaired electron in $3 d$
$Cr ^{+}=[ Ar ] 3 d^5$; five unpaired
$Mn ^{2+}=[ Ar ] 3 d^5$ electrons in $3 d$