The main flaw in Bohr's theory was that, although it explained the hydrogen atom perfectly, it explained nothing else.

All attempts to extend the theory to atoms with more than one electron failed until Schrodinger developed wave mechanics a decade later.

However, the following ideas of the Bohr theory, which were so startling to contemporary physicists, remained valid even in the later theory: the wave nature of the electron, quantization of energy in atoms, quantum numbers to describe particular energy states of an atom, and absorption and emission of energy as the atoms jump from one quantum level to another.

Above: Photograph of absorption spectra for the stars:
HD46223, a-Leonis (Regulus), b-Com, o-Draconis.