Other experiments with discharge tubes suggested the existence of a positive particle with much greater mass (the proton).

Based on this evidence Thomson proposed the first atomic model with sub-atomic particles.

Finally in the years between 1908 and 1911 Ernest Rutherford and his students Hans Geiger and Ernest Marsden performed the famous gold-foil experiment in which the nuclear arrangement of the atom was discovered.

Rutherford's vision of the atom as a kind of "solar system" in miniature is what most people probably carry around in their heads.

As appealingly simple as it is, Rutherford's model contained a serious flaw.