Bohr Model

of the Atom

1. Electrons reside in stationary states and do not radiate energy. They have well-defined energies: where Transitions can occur between them yielding light of energy: where is aborption and is emission
2. Classical laws of physics don’t apply to transistions between stationary states, but they do apply elsewhere
3. The angular momentum of the state is , where is call the Principal Quantum Number

Consequences

from planetary model Set equal to eachother you get

is called the Bohr Radius, which is the radius of the Hydrogen atom in its lowest energy state.

More specifically

See Fine Structure Constant

Emission of light occurs when the atom is in an excited state and decays to a lower energy state ()

where is the frequency of the emitted photon

Can be used to derive the Rydberg Equation

Limits

Assumes that the nucleus has infinite mass. In reality, the nucleus wobbles with the motion of the Electron. In order to account for this motion, use the reduced mass of the electron

Bohr Reduced Mass of Electron

Only works for Hydrogen atoms and other single electron atoms

Doesn’t explain other natural phenomena