Question
Pick out the isoelectronic structures from the following;
$$\eqalign{
& \left( {\text{i}} \right)CH_3^ + \cr
& \left( {{\text{ii}}} \right){H_3}{O^ + } \cr
& \left( {{\text{iii}}} \right)N{H_3} \cr
& \left( {{\text{iv}}} \right)CH_3^ - \cr} $$
A.
(i) and (ii)
B.
(iii) and (iv)
C.
(i) and (iii)
D.
(ii), (iii) and (iv)
Answer :
(ii), (iii) and (iv)
Solution :
$${\text{No}}{\text{.}}\,{\text{of}}\,{e^ - }\,{\text{in}}\,CH_3^ + = 6 + 3 - 1 = 8$$
$${\text{No}}{\text{.}}\,{\text{of}}\,{e^ - }\,{\text{in}}\,{H_3}{O^ + } = 3 + 8 - 1 = 10$$
$${\text{No}}{\text{.}}\,{\text{of}}\,{e^ - }\,{\text{in}}\,N{H_3} = 7 + 3 = 10$$
$${\text{No}}{\text{.}}\,{\text{of}}\,{e^ - }\,{\text{in}}\,CH_3^ - = 6 + 3 + 1 = 10$$
$$\therefore \,{H_3}{O^ + },N{H_3}\,{\text{and}}\,CH_3^ - \,{\text{are}}\,\,{\text{isoelectronic}}.$$