Question

How do I write the electron configuration of an oxygen molecule?

Answer 1

Aufbau Principle

• Aufabu principle determines the shell, subshell, and orbital in which the incoming electrons are to be filled according to their energy levels.
• The preference for the filling up of electrons according to their energy levels is: $1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s,5f,6d,7p,8s$
• However, molecular orbital theory describes the electronic configuration of molecular species such as oxygen molecule.
• The electronic configuration for a molecule containing 16 or more than 16 electrons according to MOT is given by:
• $\sigma 1s,{\sigma }^{*}1s,\sigma 2s,{\sigma }^{*}2s,\sigma 2p_z,\pi 2p_x=\pi 2p_y,{\pi }^{*}2p_x={\pi }^{*}2p_y,{\sigma }^{*}2p_z$

Electronic configuration of oxygen molecule:

• Oxygen molecule has 16 electrons, so the electronic configuration of oxygen molecule becomes:
• $\sigma 1s^2,{\sigma }^{*}1s^2,\sigma 2s^2,{\sigma }^{*}2s^2,\sigma 2p_z^2,\pi 2p_x^2=\pi 2p_y^2,{\pi }^{*}2p_x^1={\pi }^{*}2p_y^1,$