Question

Which of the following are isoelectronic species?

(i) $N{H}_3$
(ii) $C{H}_3^{+}$
(iii) $N{H}_2^{-}$
(iv) $N{H}_4^{+}$

Choose the correct answer from the codes given below:

• A. $\left(i\right),\left(ii\right),\left(iii\right)$
• B. $\left(i\right),\left(iii\right),\left(iv\right)$
• C. $\left(i\right),\left(ii\right),\left(iv\right)$
• D. $\left(ii\right),\left(iii\right)$
• E. None of these

Answer 1

The correct option is B $\left(i\right),\left(iii\right),\left(iv\right)$

	Species	Number of electrons
(i)	$N{H}_3$	$7+1\times 3=10$
(ii)	$C{H}_3^{+}$	$6+1\times 3-1=8$
(iii)	$N{H}_2^{-}$	$7+1\times 2+1=10$
(iv)	$N{H}_4^{+}$	$7+1\times 4-1=10$

Since (i), (iii) and (iv) contain the equal number of electrons, so these are called isoelectronic species.