Dear student,
The wave-mechanical model is a current theory describing the locations of electrons in orbit around the nucleus of an atom.The number of electrons in each shell of an atom may be described using electron notation.
A powerful model of the atom was developed by Erwin Schrödinger in 1926. Schrödinger combined the equations for the behavior of waves with the de Broglie equation to generate a mathematical model for the distribution of electrons in an atom.
Regards