Learning outcomes - after studying this topic, you should be able to:

• explain how electron sharing leads to lowering of electronic energy in terms of increasing the de Broglie wavelength.
• predict electronic configurations and bond orders for diatomic molecules, given a molecular orbital (MO) energy diagram
• predict relative binding energies and bond lengths from bond order
• recognise a bonding or antibonding orbital from the lobe representation
• recognize a σ orbital and a σ* orbital
• recognize a π orbital, a π orbital and a non-bonding orbital
• identify the valence electrons and orbitals in diatomic molecules
• distinguish between polar and apolar bonds in diatomic molecules and relate it to electron attraction of a nucleus (electronegativity)
• draw out ground state electronic configurations for molecules and molecular ions given their allowed energy levels
• calculate bond order from molecular electronic configurations
• explain the difference between paramagnetism and diamagnetism
• predict whether a molecule will be diamagnetic or paramagnetic from its orbital energy diagram
• recall the meaning of HOMO and LUMO and determine the lowest energy electronic transition

• Sections 5.5 and 6.8 (in Blackman, Bottle, Schmid, Mocerino and Wille, Chemistry, 3^rd Edition, 2015 (John Wiley) )

Electronegativity and polar molecules Tags: electronegativity | polar molecules | intermolecular forces Contributed by Adam Bridgeman

Organic functional groups Tags: functional groups Contributed by Adam Bridgeman

Molecular orbital diagrams for diatomics: bond order Tags: MO diagrams | molecular orbitals | bond order Contributed by Adam Bridgeman