A2-Level Transition Elements

  • There are five d-shaped orbitals that each occupy a different area in space around the nucleus of an atom

  • Ligands have lone pairs of electrons that repel electrons in some d-orbitals more than others as they move towards to a metal ion

  • D-orbitals have different shapes, meaning some orbitals are repelled more by approaching ligands than others – making them higher energy and the other orbitals lower energy.

  • The d-orbitals are split into two groups – high energy and low energy, with a specific energy gap between them.


d-orbital Splitting


All five d-orbitals have complicated shapes that occupy different areas around a nucleus.





















When ligands move towards a metal ion, some orbitals are closer to the ligand than others. Ligands have a lone pair of electrons which repel the electrons in d-orbitals that are close to the ligand.  Electrons in d-orbitals further away from the ligand are repelled less. Repulsion leads to high energy. This makes the d-orbitals repelled by the ligands a higher energy and the other d-orbitals a lower energy.


The d-orbitals energies are split – some are high energy, some are low energy.

















The difference in energies between the orbitals creates two sets of orbitals, high energy and low energy. The energy gap between the high and low orbitals is unique for every metal ion, although it can be changed if the ligands around the metal ion are changed, as different ligands will repel the orbitals differently.