• Quantum Mechanics governs electron motion and allows
the energies of an atom to have only discrete
values.
• The energy of an atom is said to be
quantised.
(quanta = packet)
Schrödinger
Equation
H Y = E Y
[Y - Greek psi]
Y = atomic wavefunction E = atomic energy
H = Hamiltonian operator ( incl. e-/ e- effects)
• Although Y is not
experimentally observable the function Y2 is
measurable.