Summary

A hydrogen atom can be described in terms of its wave function, probability density, total energy, and orbital angular momentum.
The state of an electron in a hydrogen atom is specified by its quantum numbers (n, l, m).
In contrast to the Bohr model of the atom, the Schrödinger model makes predictions based on probability statements.
The quantum numbers of a hydrogen atom can be used to calculate important information about the atom.

A hydrogen atom has magnetic properties because the motion of the electron acts as a current loop.
The energy levels of a hydrogen atom associated with orbital angular momentum are split by an external magnetic field because the orbital angular magnetic moment interacts with the field.
The quantum numbers of an electron in a hydrogen atom can be used to calculate the magnitude and direction of the orbital magnetic dipole moment of the atom.

The state of an electron in a hydrogen atom can be expressed in terms of five quantum numbers.
The spin angular momentum quantum of an electron is = $+ ½$ . The spin angular momentum projection quantum number is m_s $= + ½ or - ½$ (spin up or spin down).
The fine and hyperfine structures of the hydrogen spectrum are explained by magnetic interactions within the atom.

Pauli’s exclusion principle states that no two electrons in an atom can have all the same quantum numbers.
The structure of the periodic table of elements can be explained in terms of the total energy, orbital angular momentum, and spin of electrons in an atom.
The state of an atom can be expressed by its electron configuration, which describes the shells and subshells that are filled in the atom.

Radiation is absorbed and emitted by atomic energy-level transitions.
Quantum numbers can be used to estimate the energy, frequency, and wavelength of photons produced by atomic transitions.
Atomic fluorescence occurs when an electron in an atom is excited several steps above the ground state by the absorption of a high-energy ultraviolet (UV) photon.
X-ray photons are produced when a vacancy in an inner shell of an atom is filled by an electron from the outer shell of the atom.
The frequency of X-ray radiation is related to the atomic number Z of an atom.

Laser light is coherent (monochromatic and “phase linked”) light.
Laser light is produced by population inversion and subsequent de-excitation of electrons in a material (solid, liquid, or gas).
CD and Blu-Ray players uses lasers to read digital information stored on discs.