Question

Match List -I with List - II

List - I Electronic configuration of elements		List-II $\Delta _{i}$ in $kJ\, mol ^{-1}$
(a)	$1s^{2}2s^{2}$	(i)	801
(b)	$1s^{2}2s^{2}2p^{4}$	(ii)	899
(c)	$1s^{2}2s^{2}2p^{3}$	(iii)	1314
(d)	$1s^{2}2s^{2}2p^{1}$	(iv)	1402

Choose the most appropriate answer from the options given below -

• A. $(a) \to (ii),(b)\to (iii),(c) \to ( iv ),(d) \to (i)$
• B. $(a) \to (i),(b) \to (iv),(c) \rightarrow(iii),(d) \to (ii)$
• C. $(a) \to (i), (b) \to (iii), (c) \to (iv), (d) \to (ii)$
• D. $(a) \to (iv), (b) \to (i), (c) \to (ii), (d) \to (iii)$

Answer 1

Answer: (A)

(a) $1 s ^{2}\, 2 s ^{2} \to Be$

(b) $1 s ^{2} \,2 s ^{2}\, 2 p ^{4} \to O$

(c) $1 s ^{2} \,2 s ^{2} \,2 p ^{3} \to N$

(d) $1 s ^{2} \,2 s ^{2}\, 2 p ^{1} \to B$

The ionization enthalpy order is

$B < \,Be < \,O < \,N$

$Be$ has more $IE$ compared to $B$ due to extra stability & $N$ has more $IE$ compared to oxygen due to extra stability

Hence, $N \to 1402 \,kJ / mol$

$O \to 1314 \,kJ / mol $

$B \to 801 \,kJ / mol $

$Be\to 899 \,kJ / mol$