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Robert Boyle
Helped develop the definition of an element, also with the "death" of the four elements- Earth, Fire, Air, Water. -
Antoine Lavoisier
Disocovered that water was made of Hydrogen and Oxygen. Also invented the analytical balanance and showed that chemical elements were neither created nor destroyed- Conservation of Mass -
Carl Scheele
Discovered Oxygen and identified Molybdenum, Tungsten, Barium, Hydrogen, Chlorine. -
Joseph Priestley
Published Oxygen findings before Carl Scheele. -
Joseph Proust
Created Law of Definite Proportions and studied Copper Carbonate, 2 Tin Oxide, 2 Iron Sulfide. -
John Dalton
Created Modern Atomic Theory. -
Julius Plucker
Built the first Cathode Ray Tube. -
William Crookes
Discovered Cathode Ray's properties. -
Jean Baptiste Perrin
Confirmed Einstein's ideas on Browmian motion by calcuating Avogadro's Constant, proving Dalton's Atomic Theory. -
J.J. Thompson
Studied "canal rays" and found they were associated with the proton H+. Used a CRT to experimentally determine the charge to mass ratio of an electron. -
Marie and Pierre Curie
Studied Uranium and Thorium and called their spontaneous decay process "radioactivity". Also discovered radioactive elements Polonium and Radium. -
Ernest Rutherford
Studied radiations emitted from Uranium and Thorium and named them Alpha and Beta. -
Frederick Soddy
Observed spontaneous disintegration of radioactive elements into variants he called "isotopes" or totally new elements. Discovered "half life", made initial calculations on energy released during decay. -
Hans Geiger
Developed an electrical device to "click" when hit with Alpha particles. -
Robert Millikan
Measured the charge of an electron with his oil-drop apparatus. He proved Thomson's hypothesis that the mass of an electron is at least 1000 times smaller than the smallest atom. -
Ernest Marsden
Discovered structure of an atom with the "gold foi" experiment. -
James Chadwick
Using alpha particles discovered a neutral atomic particle with a mass of a proton- Neutron.