Chemistry · Chapter 8

Fill a Molecular Orbital Diagram

Pick a diatomic and the diagram fills itself from the bottom up. Watch where the last electrons land, then read the bond order and the magnetism straight off the picture.

The diagram atomic orbitals outside · molecular orbitals in the middle

What you are seeing

Pick a molecule.

Pick a diatomic

The verdict

2bond order paramagnetic
Electrons placed12
In bonding orbitals8
In antibonding orbitals4
Bond order sum(8 − 4) / 2 = 2
Unpaired electrons2
Measured bond length121 pm
Level order in useO and F order

Electron arrangement

Swap the level order

Each molecule loads with the order it really uses. Force the other one and see what it would wrongly predict. This is why B2 is the test case that settles the question.