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Through experiments John Dalton discovers that matter is consisted of elementary lumpy particles (atoms).
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Thomson discovered the electron and made a model for the structure of the atom - it ended up looking like raisins stuck on the surface of a lump of pudding. He knew that electrons had a negative charge and that matter must have a positive charge.
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Rutherford inedtifies the particles of the nucleus as discrete positive charges of matter and he also discovered protons.
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Bohr's theory states the electrons don't spiral into the nucleus. He came up with two rules (which also started a new approach to science because rules had to fit the observation regardless of conflictions with the current theories), the first rule states that electrons can orbit only at certain allowed distances from the nucleus and the second rules states that atoms radiate energy when an electron jumps from a higher-energy orbit to a lower-energy orbit.
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He proposed that we go all the way with particle waves and try to form a model of the atom on that basis. His theory was similar wo a harmonic theory for a violin string, but the vibrations traveled in circles.