Question

Question #c2a2e

Answer 1

Here is a simple version of the molecular orbital diagram for CO.

The electron configuration of carbon is [He]`2s^2 2p^2`. We see these orbitals on the left hand side of the diagram.

The electron configuration of oxygen is [He]`2s^2 2p^4`. We see these orbitals on the right hand side of the diagram.

Now we generate the molecular orbitals of CO in the middle of the diagram.

As the two atoms approach each other, their atomic orbitals interact to form molecular orbitals.

The C `2s` and the O `2s` orbitals merge to form a `2sσ` and a `2sσ`* orbital. These are at the bottom of the diagram

The C `2p_z` and the O `2p_z` orbitals merge to form a `2pσ` and a `2pσ`* orbital. These are at higher energies than those formed by `2s` overlap.

The C `2p_y` and the O `2p_y` orbitals merge to form `2pπ` and `2pπ`* orbitals.

The C `2p_x` and the O `2p_x` orbitals also merge to form `2pπ` and `2pπ`* orbitals.

These orbitals are degenerate. They have energies above and below their `2pσ` and `2pσ`* counterparts.

Now we add electrons to these molecular orbitals. C contributes 4 valence electrons; O contributes 6.

We add the 10 electrons to the molecular orbitals following the Aufbau principle and Hund's Rule.

We end up with a diagram like that above.