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He invented the analytical balance and showed that chemical elements were neither created nor destroyed, Also he discovered that water is made of hydrogen and oxygen
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Believed the atom was based on measureable properties of mass.
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While he was studying the effect of x-rays on photographic film, he stumbled into some chemicals that would spontaneously decompose and give off pentrating rays.
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Studied "canal rays" and discovered that they were associated with the proton H + . he also discovered the mass ratio
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Marie introduced the theory of radioactivity. Marie and Pierre discovered the radioactive elements Polonium and Radium.
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Explained hot glowing matter using quanta.
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He discovered the charge and mass of an electron by doing an oil drop experiment charge=(e=1.602 x 10 -19 coulomb) and the mass=(m = 9.11 x 10 -28 gram).
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He discovered that the nucleus was very dense,very small and had a positive charge. He also assumed that the electrons were located outside the nucleus, he later on was proved to be correct.
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He wrote "The atomic number of an element is equal to the number of protons in the nucleus". This later on became the structure of the periodic table instead of atomic mass.
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Proposed a theory of the atomc structure, by using the periodic table. Introduced the theory that electrons orbit around the nucleus of an atom.
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Believed that the atom was only made of waves, but not particles.
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Proposed Principle of Indeterminancy - you can not know both the position and velocity of a particle.
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Discovered the neutron, which he realized had a mass that was close to a proton
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Believed atoms could be any size and that they were induvidually created and couldn't be seperated.
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Aristotle believed that the atom was made from the portions of the four elements; water, fire, wind, and earth. He didn't believe that there wasn't a "smallest' part of matter.
