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100
Democritus
Democritus Democritus lived from 460-370 B.C.E, He made the statement that matter was made of atoms, and that they were indestructible. He said that they will always be in motion. -
Period: 100 to
Atomic Theory
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John Dalton
John Dalton
Dalton was born on September 6, 1766 and died July 26, 1844.
He said that atoms were indetructible. They thye all had a certain size and mass. Dalton named his model the "Billiard Ball Model" -
J.J Thomson
J.J Thomson JJ was born December 18, 1856 and died on August 30, 1940. Thomson discovered the electron. He used cathode rays to show that atoms had negative particles. -
Max Planck
Max Planck Planck was born on April 23, 1858 and died October 4th, 1947. Planck had a lot of contributions to the theoretical physics. -
Ernest Rutheford
Ernest Rutheford Rutheford was born on August 30, 1871 and died on October 19, 1937. Rutheford described that the atom has a positive nucleus surrounded by negative electrons. -
Niels Bohr
Niels Bohr Bohr was born on October 7th, 1885 and died on November 18th, 1962. Bohr explained how electrons can have orbits around the nucleus. -
James Chadwick
James Chadwick Chadwick was born on October, 20th 1891 and died on July 24th, 1974. Chadwick proved the existence of nuetrons.
