Discovery of the Subatomic Particles

• In 1886, Eugen Goldstein discovered cations using cathode ray tubes
• Ions: particles that gained/lost electrons
• Cations: positive ions, electron loss


  e.g. Hydrogen: P = 1, E = 1

  Hydrogen+: P = 1, E = 0
• Anion: negative ions, electron gain


  e.g. Hydrogen: P = 1, E = 1

  Hydrogen-: P = 1, E = 2
• Cathode Ray Tube: presentation screen that produces pictures as a video signal
• In 1897, J.J. Thompson determined the charge to mass ratio using cathode ray tubes
• Charge to Mass Ratio: e/m = 1.758820 x 10^11 c/kg
• Ernest Rutherford discovered the nucleus and proton using the gold foil experiment/alpha scattering experiment
• In 1909, Robert Millikan demonstrated the atomic structure of electricity using the falling drop/oil drop method (1.602 x 10^-19 C)
• James Chadwick discovered the neutron