Answer:
Thompson discovered the electron and also stated that these electron are not found with in the nucleus of an atom which is contrasting to his plum pudding theory
Step-by-step explanation:
J. J. Thomson has used a cathode ray tube to conduct his experiment. He projected the cathode rays towards positively charged alpha particles at thin gold foil and found that all the cathode rays have easily passed through this foil carrying positive charge but when the same rays were projected to a negative metal plate , the cathode rays moved away from the metal plate. Through this observation, Thompson concluded that cathode rays are negatively charged and there is something negative with in a matter that he later termed as electron which are not confined with in the nucleus of atom but they revolve around the nucleus. However, in pudding model he said that atom is a positively charged pudding with electrons embedded in it.