Molecular Orbital Summary of Second Row Diatomic Molecules In case of paired electrons the molecule is diamagnetic. Summary of Electronic Configurations of Molecular Orbitals of 1 st and 2 nd row diatomic Moleculesĭetermination of Magnetism Behaviour: If any molecule has unpaired electron in molecular orbital diagram, then it is paramagnetic.

Higher is the BO, stronger is the bond.

If bond order = 0, it means species does not exist.

BO must be greater than 0 for a stable molecule to form.

Bond order (BO) is a measure of net bonding interactions.

of electron in bonding Mo’s N a = No of electron in antibonding Mo’s.

In these molecular orbitals electrons are filed according toAufbau principle.įrom H 2 to N 2: σls < σ * ls < σ2s < σ * 2s < π2p y = π2p z < σ2p x < π * 2p y = π * 2p z < σ * 2p x For O 2 & F 2: sls < σ * ls < σ2s < σ * 2s < π2p x < π2p y = π2p z < σ * 2py < π * 2py = π * 2pz = σ * 2p x.

Each molecular orbital can hold 2 electrons with opposite spins.Molecular electron configurations can be written similar to atomic electron configurations.Due to this s-p mixing, the energies of all the four orbitals change in such a way that the resulting MOs σ(2s) and σ*(2s), which also contain some p character, become more stable and are thus lowered in energy whereas the MOs σ(2p z) and σ*(2p z) which contain some s character also now become less stable and are thus raised in energy.Įlectron Configurations in MO: (Filling of bonding orbitals in order of increasing energy) In fact, all the four MOs acquire a mixed sp character.

Similarly, σ*(2s) with σ*(2p z) can also mix resulting that σ(2s) and σ*(2s) MOs do not retain the pure s character and the σ(2p z) and σ*(2p z) MOs do not retain the pure p character. If the energy differences between 2s and 2p atomic orbitals are small, there is a possibility of mixing of molecular orbitals σ(2s) with σ(2pz) as they are of the same symmetry. Homonuclear diatomic molecule with Z > 14 (O 2 onwards) Molecular orbital Diagrams: Homonuclear Diatomic Molecules up to N 2 (i.e.

Molecular orbital theory diagram