Matter is made of small indivisible particles. Democritus called these particles atoms.
1803 - 1804
Developed an atomic theory stating that spherical atoms had measurable properties of mass.
1897 - 1898
Discovers the electron and used cathode ray tubes to determine the charge to mass ratio. Found canal rays were associated with a proton
1899 - 1900
Discovers alpha and beta rays emitting from radium.
1905 - 1906
Publishes theory on special relativity and states that matter can be converted into energy.
1911 - 1912
Performed the gold foil experiment to determine that the nucleus is a small, dense, and positively charged part of the atom, based on the assumption that electrons are on the outside of the nucleus. Develops the plum pudding model of the atom.
1913 - 1914
Publishes paper regarding combining nuclear and quantum theories.
Louis Victor de Broglie
1923 - 1924
Electrons are similar to both particles and waves.
Werner Heisenberg, Max Born and Erwin Schodinger
1925 - 1926
Developed quantum mechanics
1927 - 1928
Used the frequencies based on spectra lines to describe atoms.
1930 - 1931
Saw electrons as a continuous cloud and developed wave mechanics to be a mathematical model for the atom.
1932 - 1933
Discovered neutral atomic particle with similar mass to a proton, the neutron by using alpha particles.