Bohr model

of: the hydrogen atom

is: now supplanted but remains historically important as the first theoretical account of atomic structure to make use of quantum physics. [P8.2]

was formulated: by Niels Bohr (1885-1962) in 1913. [P8.2]

postulates: (1) that the negatively charged electron is held in a circular orbit around the positively charged nucleus by the Coulomb force between them;

(2) that the range of allowable orbits is restricted by the requirement that the angular momentum of the orbiting electron is quantized in units of where is Planck's constant;

(3) that, contrary to classical physics, the orbiting electron does not continuously lose energy through the emission of electromagnetic radiation;

(4) that electromagnetic radiation is emitted when the electron makes a transition from an initial orbit of energy to a final orbit of energy and that the frequency of that radiation is given by the Planck-Einstein formula as [P8.2]

explains: many features of the spectrum of atomic hydrogen, including Balmer's formula. [P8.2, P11.3]

may be: extended to atoms other than hydrogen, but only with limited success.