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460 BCE
Democritus
He came up with what he called the theory of the universe. He was the first person to use the term Atom as well. -
384 BCE
Aristotle
He denied the existence of atoms, and criticized Democritus. He was so great in science that his denial of atoms went unchallenged for nearly 2000 Years. -
Antoine Lavoisier
Was one of the first to use an analytical balance to monitor chemical reactions. He studied the thermal decomposition of mercury and helped develop the atomic theory. -
John Dalton
He was the first to adapt Democritous' theory into the first atomic model. He discovered the atomic theory. -
J.J Thomson
He is a physicist who discovered the electron. He used his research on cathode ray tube technology in his discovery and found out about negative charge and that negative charge is inside an atom. -
Robert Millikan
Oil drop experiment determined the charge and the mass of an electron. -
Ernest Rutherford
He set up the Gold Foil Experiment and created the nuclear model. He founded and named the nucleus. -
Niels Bohr
He answered the questions of Rutherford's model with why electrons did not collapse into the nucleus. He helped with the model that became known as the Rutherford-Bohr Model. -
Erwin Schrödinger
revolutionary physicist who used Heisenberg's uncertainty principle to come up with the atomic model that we still use today; the Schrodinger atomic model aka the cloud model. -
Werner Heisenberg
Proposed the Principle of Indeterminacy. Described atoms by means of formula connected to the frequency of spectral lines. -
Louis de Broglie
He came up with the quantum theory and predicted the wave nature of electrons. -
James Chadwick
He used alpha particles to discover a neutral atomic particle with a mass close to a proton. Then discovered the neutron.