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Modern Atomic Theory
John Dalton discovered the Modern Atomic Theory. Dalton proposed that each chemical element is composed of atoms of a single, unique type, and though they cannot be altered or destroyed by chemical means, they can combine to form more chemical compounds. -
Proton Charge
John Dalton discovered that a proton is a positively charged particle with a charge, equal and opposite to that of electron. -
Charge/Mass of Electrons
J.J. Thomson identified the electron as a particle. An electron has a mass that is approximately 1/1836 that of the proton. Electrons have a negative charge. -
Positively Charged Nucleus
Ernest Rutherford conducted his Gold Foil Experiment and conclueded that that a positively charged nucleus was surrounded by negatively charged electrons. The negatively charged electrons were the gamma rays. The nucleus was the gold foil and some of the gamma rays passed throught the foil because positive and negative charged react. -
Neutral Neutron
Chadwick proved that the atomic nucleus contained a neutral particle -
Energy Levels
Niels Bohr acknowledged that electrons existed at set levels of energy -
Quarks
Murray Gell-Mann and George Zweigin discovered that electron-proton scattering experiments indicated that the electrons were scattering off three point-like constituents inside the proton -
Leptons
Martin L. Perl discovred that a lepton is alike to the electron, the carrier of electrical current.
