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101
Thales of Miles
600 BC
Declared all life came from water. Everything was made of water. -
101
Democritus
460-370 BC
thought everything was made of atoms -
101
Aristotle
thought everything was earth, water, air, and fire -
Sir Isaac Newton
Thought that atoms moved around and were small -
Dalton
- elements are made of extremely small particles called atoms
- atoms of a given element are identical in size, mass, and other pe=roperties;
- atoms cannot be subdivided, created, or destroyed 4.atoms of different elements combine in simple whole number ratios to form chemical compounds
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Becquerel
descovered radioactivity -
JJ thomson
descovered electron (two thousand times lighter than hydrogen) -
Ernest Ruthaford
atoms contain a nucleus made of protons surrounded by electrons -
Robert Millikan
determined the charge and mass of an electron -
Gold Foil Experimen
Ruthaford fired helium atoms at a gold sheet of paper but they hit the nucleus and bounced back. He didn't think they would -
Bohr
Created bohr model and said everthing was on fixed paths and couldn't be inbetween -
Francis Aston
Descovered and studied isotopes. Also did the whole number rule -
Schrodinger
made the quantum model -
James Chadwick
discovered evidence towards the existance of Neutons