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Thales of Miletus was the first person to investigate the basic principles publically.
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Used thought experiment to develope a basic idea of the first atom.
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Did not believe in the atom theory. Aristotle thought of the Earth, wind, air, and fire theory.
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Said that the atom was held together by a force.
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Came up with the first atomic theory and discovered that water is in the air.
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Discovered Radioactivity
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Was the first to discover atoms had a negative and positive charge
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Used the oil drop experiment and found the charge of an indiviual electron.
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Particles were fired through a thin gold sheet to see if they would pass straight through.
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Used the gold foil experiment and discovered that all mass in found in the nucleus.
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Discovered that the electrons in an atom had certain orbits. This is what keeps electrons from spiralling inward and outward.
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Identified 212 natural isotopes
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Used mathematical equations to prove that electrons are in certain places.
