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400
Democritus
Democritus thought there were thing were so small they could not be made any smaller or cut any smaller Stuewer, Roger H. "World Book Online Reference Center | Online Reference Book| Online Encyclopedia." World Book. Roger H. Stuewer, 20 Feb. 2015. Web. 20 Feb. 2015. -
Period: 400 to 400
Democritus
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John Dalton
Saffman, Mark. "World Book Online Reference Center | Online Reference Book| Online Encyclopedia." World Book. Mark Saffman, 25 Feb. 2015. Web. 25 Feb. 2015. In 1803, a British chemist named John Dalton developed an atomic theory to explain this discovery. -
Thomson
<a href='http://Huffman, Carl A. "World Book Online Reference Center | Online Reference Book| Online Encyclopedia." World Book. Carl A Huffman, 20 Feb. 2015. Web. 20 Feb. 2015.' >Worldbook</a>H e thought atoms had negative charged particles, he used cathode rays that had negative charged particles. -
Rutherford
<a href='http://Bennett, Linda. "What Rutherford Discovered." Rutherford. Linda Bennett, 2012. Web. 23 Feb. 2015.' >Rutherford</a>He discovered the nucleus of the atom, HE used gold foil he thought they would go staight through the foil. The ray deflected went in different direction while some went straight when he concluded they moved. -
Niels Bohr
Bohr suggested that electrons could travel only in a certain set of orbits around the nucleus. -
Erwin Schrodinger
Schrodinger and Heinsberg discovered that you cannot know the exact position and momentum of the electrons.