How does a molecular orbital differ from an atomic orbital?
An atomic orbital extends over one atom. A molecular orbital extends over more than one atom.
An orbital is a region in space where an electron is most likely to be found.
The simplest atomic orbital is the spherical
When two H atoms get close enough, their orbitals merge to include both nuclei. We then have a molecular orbital.
Actually, we can get two molecular orbitals, because the electrons behave as waves.
They can either reinforce or cancel each other in the region between the two nuclei. So the molecular orbitals can be either bonding or antibonding.
But the main point is, a molecular orbital extends over more than one atom.