- Bohr based his model on the energy (light) emitted by different atoms
- Each atom has a specific spectra of light
- Light travels as photons
- The energy photons carry depends on their wave length
To explain this emission spectra Bohr suggested that electrons occupy shells or orbitals.
- Electrons exist in orbitals
- When they absorb energy they move to a higher orbital
- As they fall from a higher orbital to a lower orbital they release energy as a photon of light