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624-547 B.C. Thales was a Greek man who claimed that Water is the basic substance of our world.
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500-428 B.C., 484-424 B.C. Anaxagoras believed that changes in matter are due to different orders of "invisible" particles. Empedocles simplified those invisible particles into four seperate categories; Earth, Air, Fire, Water.
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460 - 370 B.C. Democritus was the first greek to come up with the idea of the Atom. His belief is that the universe is made up of an almost infinite number of particles that differ from each other in almost every way possible. He called those particles "Atoms".
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Issac Newton suggested that Atoms are held together by forces. He also said that "matter is formed of solid, massy impenetrable particles”.
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Dalton proposed that all matter is made up of atoms that can't be created or destroyed. He believes that there are 3 types of atoms; Simple (elements), Compound (simple molecules), and complex (complex molecules).
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Georgeintroduced the idea of electrons and estimated the charge of a hydrogen atom.
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Joseph John Thomson and Kelvin created the first model for an atom.
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Millikan managed to measure the charge of an electron using a drop of oil.
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Ernest was the first man to split an atom.
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By measuring the wavelengths from x-rays of certain metals, Moseley was able to figure out how many positive charges there are in an atom.
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Neils published a book on his theory. His belief is that electrons orbit around the center of an atom.
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James discovered the neutral charge of the atom which was previously unknown of.