Question
Which group contains coloured ions out of
$$\eqalign{
& \left( {\text{i}} \right)\,C{u^{2 + }} \cr
& \left( {{\text{ii}}} \right)\,T{i^{4 + }} \cr
& \left( {{\text{iii}}} \right)\,C{o^{2 + }} \cr
& \left( {{\text{iv}}} \right)\,F{e^{2 + }} \cr} $$
A.
(i), (ii), (iii), (iv)
B.
(i), (iii), (iv)
C.
(ii), (iii)
D.
(i), (ii)
Answer :
(i), (iii), (iv)
Solution :
$$C{u^{2 + }}\left[ {Ar} \right]3{d^9},T{i^{4 + }}\left[ {Ar} \right]3{d^0},$$ $$C{o^{2 + }}\left[ {Ar} \right]3{d^7},F{e^{2 + }}\left[ {Ar} \right]3{d^6}$$ (i), (iii), (iv) are coloured ions hence the answer is B.