Answer
J.J Thomson: Showed the existence of electrons
Ernest Rutherford: Showed that an atom has a positively charged nucleus, where the mass is concentrated.
Combined: It led to the idea that an atom has a positively charged mass in the center with negatively charged particles moving around the nucleus at a distance.
Work Step by Step
J.J. Thomson used cathode ray tubes to show that a negatively charged particle (electrons) exist in atoms.
Ernest Rutherford conducted the Gold Foil Experiment and concluded that there is a positively charged mass in the center of an atom.
