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Period: 300 to
Scientists
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322
Aristotle
He did not believe in atoms. He thought everything was made from 4 elements: Earth wind water and fire. -
370
Democritus
Developed the theory that everything is made up of atoms. -
John Dalton
Made his own atomic theory that is also known as "Dalton's 5 postulates" -
William Crooke
He discovered the element thallium. Mades crookes tube that is used in studies of cathode rays. -
John Newlands
The "law of octaves" says if the chemical elements are arranged according to atomic weight, the ones that have similar properties happen after each interval of seven elements. -
Dmitri Mendeleev
Made the Periodic Table. It was arranged according to atomic weight and similar properties. -
Ernest Rutherford
known as the father of physics. He discovered the neutron -
J. J. Thomson
Discovered the Electron. He also made the Plum Pudding Model -
Niels Bohr
Determined that electrons travel orbits around the nucleus. Created a new atomic model -
James Chadwick
discovered the neutron is in the nucleus in 1932
