The Bohr model shows the atom as a tiny, positively-charged center, surrounded by electrons. These electrons travel in small circular orbits around the nucleus. The attraction of the electrons was electrostatic forces. The energy of the electrons depended on the size of the orbit so more energy equals a greater orbit.
Bohr also discovered that radiation occurred when the electron moved from one orbit to another. He discovered that electrons have fixed orbits but, they can jump from orbit to orbit by either emitting or absorbing a photon with the appropriate wavelength.Learn more about Atoms & Molecules