What is the Bohr model of the atom?
The Bohr model was proposed by Niels Bohr in an attempt to explain why electrons don't crash into the nucleus. According to classical physics opposites attract and likes repel. However, electrons (-) don't move into the nucleus (+).
Bohr suggested that this was because the electrons were in energy levels in the atomic space and moved from level to level by absorbing or releasing photons of certain frequencies.
Bohr used Max Planck's ideas on quanta and the work of Bunsen and Kirchhoff in spectroscopy to support his model.
The Bohr model revealed the problem with the current theories and need for a new physics.