J.J. Thomson began experimented with cathode ray tubes. Cathode ray tubes are sealed glass tubes from which most of the air has been evacuated. A high voltage is applied across two electrodes at one end of the tube, which causes a beam of particles to flow from the cathode (the negatively-charged electrode) to the anode (the positively-charged electrode). The tubes are called cathode ray tubes because the particle beam or “cathode ray” originates at the cathode. Thomson placed two oppositely-charged electric plates around the cathode ray. The cathode ray was deflected away from the negatively-charged electric plate and towards the positively-charged plate. This indicated that the cathode ray was composed of negatively-charged particles. The cathode ray is composed of negatively-charged particles. Thomson’s discoveries were gradually accepted by scientists. The cathode ray particles were eventually got famous and named as electrons.
Rutherford’s gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom. n Rutherford’s gold foil experiment, a beam of alpha that was shot at a thin sheet of gold foil. Most of the particles passed straight through the gold foil, but a small number were deflected slightly, and an even smaller fraction were deflected more than 90 degrees from their path. This led Rutherford to propose the nuclear model, in which an atom consists of a very small, positively charged nucleus surrounded by the negatively charged electrons. Based on the number of alpha particles deflected in his experiment, Rutherford calculated that the nucleus took up a tiny fraction of the volume of the atom.