Chemical Bonding and Molecular Structure - Result Question 107
####110. The pairs of species of oxygen and their magnetic behaviours are noted below. Which of the following presents the correct description?
(a) $O_2^{-}, O_2^{2-}-$ Both diamagnetic
[2011 M]
(b) $O^{+}, O_2^{2-}-$ Both paramagnetic
(c) $O_2^{+}, O_2-$ Both paramagnetic
(d) $O, O_2^{2-}-$ Both paramagnetic
Show Answer
Solution:
- (c) MOT configurations of $O_2$ and $O_2^{+}$:
$O_2^{+}:(\sigma 1 s)^{2}(\sigma^{} 1 s)^{2}(\sigma 2 s)^{2}(\sigma^{} 2 s)^{2}(\sigma 2 p_z)^{2}$
$(\pi 2 p_x^{2}=\pi 2 p^{2})(\pi^{} 2 p_x{ }^{1}=\pi^{} 2 p^{1} _{y})$
Number of unpaired electrons $=2$, so paramagnetic.
$O_2:(\sigma 1 s)^{2}(\sigma^{} 1 s)^{2}(\sigma 2 s)^{2}(\sigma^{} 2 s)^{2}(\sigma 2 p_z)^{2}$
$(\pi 2 p^{2}=\pi 2 p^{2} _{y})(\pi * 2 p_x{ }^{1}=\pi * 2 p^{0} _{y})$
Number of unpaired electrons $=2$, so paramagnetic.
