Answer
The Coulomb force between the proton and electron causes the electron to move in a circular orbit around the proton.
Only some specific orbits of the electron around the proton are stable.
When the electron falls from a higher energy state to a lower energy state, a photon is emitted.
The angular momentum determines the size of allowable electron orbits.
Work Step by Step
Danish physicist Niels Bohr described a model of the hydrogen atom using four assumptions:
The Coulomb force between the proton and electron causes the electron to move in a circular orbit around the proton.
Only some specific orbits of the electron around the proton are stable.
When the electron falls from a higher energy state to a lower energy state, a photon is emitted.
The angular momentum determines the size of allowable electron orbits.
