Thomson discovered the electron, the first subatomic particle. In 1904, Thomson proposed atomic model where electrons are embedded within spherically distributed, positive charge (so-called "plum pudding" model).
J.J. Thomson's experiments with cathode ray tubes showed that all atoms contain tiny negatively charged subatomic particles or electrons. Thomson proposed the plum pudding model of the atom, which had negatively-charged electrons embedded within a positively-charged "soup."
