In 1911, Rutherford presented a model of atom called Rutherford's model, according to which the mass of the atom and its whole positive charge are concentrated at the centre of the atom in a nuclear radius. Around the nucleus are distributed electrons in a hollow sphere and the total negative charge of the electron is equal to the positive charge of the nucleus. Rutherford assumed that the electrons in the atom are not stationary, but are revolving around the nucleus in different circular orbits and the necessary centripetal force is provided by the electrostatic force of attraction between the electron and the nucleus.
