Notes On Millikan, Goldstein, Chadwick And Subatomic Particle Data

• Discovered electron (negatively charged particle
• Charge to mass ratio of e^- is constant, this means only one type of electron
• From results of his experiment, Plum pudding Model of Atom

• Determined actual charge and mass of e^-, mass of electron = 9.11E-28 g
• Used a sensitive oil dropping equipment
• Discovery made in 1909

• Discovery of proton (some people dispute this)
• When, about same time as electron, also disputed

• Discovery of neutron, 1932

• Proton (p⁺), positively charged, mass = 1.67E-24 g, located in nucleus
• Neutron (n⁰), neutral charge, mass = 1.67E-24 g, located in nucleus
• Electron (e^-), negatively charged, mass = 9.11E-28 g, located outside nucleus
  • electron mass is approximately 1/2000 mass of proton or neutron (actually is 1/1840)
    
• Note: Yes, these subatomic particles are made up of even smaller particle, but that is for physic to explain NOT chemistry.