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460 BCE
Democritus
Democritus lived from 460 BC to 370 BC in Abdera, Thrace. Democritus hypothesized that the atom is invisible, cannot be destroyed, cannot change in shape, size, and temperature, and are constantly moving. -
Antoine Lavoisier
He began the conversation on what an atom was exactly. -
John Dalton
John Dalton lived from September 6, 1766 to July 27, 1844 in Eaglesfield, United Kingdom. Dalton’s atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass. -
JJ Thomson
JJ Thomson lived December 18, 1856 to August 30, 1940.He discovered the electron and that an atom can be divided and that atoms are made of positive and negative cores. -
Max Planck
Max Planck lived from April 23, 1858 to October 4, 1947 in Kiel, Germany. Max Planck was the initial founder of the quantum theory which was a theory of matter and energy based on the concept of quanta, especially quantum mechanics. -
Marie Curie
Marie Curie lived from November 7, 1867 to July 4, 1934. She discovered radium and polonium and her and her husband discovered radioactivity. -
Robert Millikan
Robert Millikan lived from March 22, 1868 to December 19, 1953 in Illinois, USA. An experiment performed by Robert Millikan in 1909 determined the size of the charge on an electron. He also determined that there was a smallest 'unit' charge, or that charge is 'quantized'. -
Ernest Rutherford
He discovered alpha and beta radiation, the atomic nucleus, nuclear reactions, and the proton. -
Albert Einstein
Albert Einstein lived from March 14, 1879 to April 18, 1955. He discovered mass- energy equivalence; through his famous formula E=mc². He also formulated the photon theory of light and explains the photoelectric effect. -
Niels Bohr
He remodeled the atom so electrons orbit around the nucleus while all other orbits were forbidden. -
Erwin Schrodinger
Erwin Schrodinger lived from August 12th 1887 to January 4,1961. He used mathematical equations to find the likelihood of finding an electron in a certain positions. -
Louis De Broglie
Louis De Broglie lived from August 15, 1892 to March 19, 1987 in Dieppe, France. He was known for his research on the quantum theory, predicting the wave nature of electrons, and his experiments that indicated that the electron must move around a nucleus and that, for reasons then obscure, there are restrictions on its motion. -
Werner Heisenberg
He contributed to the theory of quantum mechanics. -
James Chadwick
He discovered the neutron.
