Classical electrodynamics is based on the generation of electromagnetic fields by charged bodies, and on the forces acting on charged bodies propagating in electromagnetic fields. These concepts are used in order to describe electron–electron scattering, as well as the scattering of two beams of electrons, at the classical level. In quantum electrodynamics, photons can be emitted and absorbed by charged particles. Within this framework, electron–electron scattering is described by the exchange of photons between the electrons. The results for the scattering angles are similar to, but slightly different from, those in classical electrodynamics. The internal angular momentum (spin) is introduced, and the Bohr atomic model is discussed.