Chemical Bonding And Molecular Structure Ques 12
12. Which of the following has the minimum bond length?
[2011]
(a) $O_2^{+}$
(c) $O_2{ }^{2-}$
(b) $O_2^{-}$
(d) $O_2$
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Answer:
Correct Answer: 12.(a)
Solution:
(a) $O_2(16): KK(\sigma 2 s)^{2}(\sigma * 2 s)^{2}(\sigma 2 p_z)^{2}(\pi 2 p_x)^{2}$
$(\pi 2 p_y)^2,(\pi^* _2 p_y)^1=(\pi^* _2 p_x)^1$, B.O.: 2
$O_2^{+}$(15): Remove one electron from $\pi^{*} 2 p_y$ from
$O_2$, B.O.: 2.5
$O_2{ }^{-}(17): KK(\sigma 2 s)^{2}(\sigma * 2 s)^{2}(\sigma 2 p_z)^{2}(\pi 2 p_x)^{2}$
$(\pi 2 p_y)^{2},(\pi * 2 p_x)^{2}(\pi * 2 p_y)^{1}$, B.O.: 1.5
$O_2{ }^{2-}(18): KK(\sigma 2 s)^{2}(\sigma * 2 s)^{2}(\sigma 2 p_z)^{2}(\pi 2 p_x)^{2}$ $(\pi 2 p_y)^{2},(\pi * 2 p_x)^{2}(\pi * 2 p_y)^{2}$
Since, the bond length decreases as the bond order increases, hence, $O_2{ }^{+}$have least bond length.