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369 BCE
Democritus
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John Dalton
John Dalton is an English chemist who's theory is called "Dalton's Atomic Model". He discovered that all elements are made of atoms and they are impossible to divide or destroy. Another thing Dalton discovered that all atoms of the same elements are similar while atoms of different elements are not and how a combinations of different elements/molecules make a compound.
The atoms in those elements/molecules need a ratio in definite whole numbers -
J.J. Thompson
J.J. Thomson was an English scientist who discovered electrons. He was experimenting with gas discharge tubes when he noticed that there was a movement in one of the tubes.He named the movements cathode rays which were moving from the negative end of the tube to the positive. This meant that he had discovered negatively charged particles that he called electrons. -
Niels Bohr
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Ernest Rutherford
