Showed that electrons can be diffracted by a nickel crystal. This indicates that electrons have wave properties . Electrons in an atom behave as standing waves. Only certain wavelengths are possible for standing waves. H is an operator.
E is the energy of the electron.
Y is the wave function of the electron and describes the properties of the electron. It also tells us where the electron can usually be found when in a given energy state. Each orbital can be specified by 3 quantum numbers which describe the various properties of the orbital. It also determines the energy of the orbital. Sign of wave function is important for bonding and hybridization.