question_answer 64)

  Which of the following options represents the correct bond order? (a) \[O_{2}^{-}>{{O}_{2}}>O_{2}^{+}\]   (b) \[O_{2}^{-}<{{O}_{2}}<O_{2}^{+}\]  (c) \[O_{2}^{-}>{{O}_{2}}<O_{2}^{+}\]               (d) \[O_{2}^{-}<{{O}_{2}}>O_{2}^{+}\]

Answer:

  (b) \[{{O}_{2}}:\,\,\,\,KK\sigma {{(2s)}^{2}}{{\sigma }^{*}}{{(2s)}^{2}}\sigma {{(2{{p}_{z}})}^{2}}\pi {{(2{{p}_{x}})}^{2}}\pi {{(2{{p}_{y}})}^{2}}{{\pi }^{*}}{{(2{{p}_{x}})}^{1}}\]\[{{\pi }^{*}}{{(2{{p}_{y}})}^{1}}\] \[{{\pi }^{*}}{{(2{{p}_{y}})}^{1}}\] \[O_{2}^{+}:\,\,\,\,KK\sigma {{(2s)}^{2}}{{\sigma }^{*}}{{(2s)}^{2}}\sigma {{(2{{p}_{z}})}^{2}}\pi {{(2{{p}_{x}})}^{2}}\pi {{(2{{p}_{y}})}^{2}}{{\pi }^{*}}{{(2{{p}_{x}})}^{1}}\]Bond order, \[{{O}_{2}}\,\,\,\,\,\,\,\,\,\frac{8-4}{2}=2.0\] Bond order, \[O_{2}^{-}\,\,\,\,\,\,\,\,\,\frac{8-5}{2}=1.5\] Bond order \[O_{2}^{+}\,\,\,\,\,\,\,\,\,\frac{8-3}{2}=2.5\] \[\therefore \]  \[O_{2}^{+}>{{O}_{2}}>O_{2}^{-}\]or \[O_{2}^{-}<{{O}_{2}}<O_{2}^{+}\]