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He developed the theory that all matter consisted of four elements: Earth, Air, Water and Fire. Aound the year 400B.C
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He discovered the idea of an atom 440B.C
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discovered oxygen in 1778 Hydrogen in 1783. and said that matter cannot destroyed during a chemical reaction even tho its physical properties are changed
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law of definite proportions in 1794
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discovered Atomic Therory and the closest person to come up of what a atom looks like. 1803
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element thallium 1961
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discovered electrons in 1897
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founded radioactvity by accident in 1898. (Bq)
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Discovered Radium & Poloniem in 1898
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found the charge of an electron. 1909
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came up with the periodic table and atomic number 1912
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atomic structure in 1913
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discovered protons in 1919
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Discovered the nuetron in 1932
