Found some notes in a pile on the floor...helpful there =)
Bohr's theory retains the classical idea that electrons move in circular orbits about a central nucleus. But since the electron does not continuously radiate energy, Bohr concluded that Maxwell's classical theory of electromagnetism does not apply on an atomic scale. He took inspiration from the work of Planck and proposed that the atomic electrons are restricted to certain orbits (known as stationary states, since they are stable and not evolving into something different) for which the energy of the electron is quantised. Applying Einstein's photon model of electromagnetic radiation, he further assumed that when an electron changes its orbit (from an initial state of energy Ef to a final state of energy Ef) a single photon is released with an energy hf , given by:
hf = Ei - Ef
In other words, the frequency f of the emitted radiation is determined by the separation of the energy levels of the two "stationary" states and is not necessarily equal to the classical frequency of the orbital motion. This prediction about the frequency of the emitted radiation allows Bohr's model to be tested experimentally.