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Democritus believed that all matter consisted of tiny particles that could not be divided.
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John Dalton believed that atoms were tiny particles that were indestructible and had no internal structure.
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J.J. Thomson disovered the electron. He also pictured electrons embedded in a sphere of positive electrical charge.
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Hantaro Nagaoka theorized that atoms had a central nucleas and that electrons move in rings.
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Rutherford stated that an atom has a dense positively charged nucleas. he also said electrons move randomly around it.
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Niels Bohr theorized that elctrons moved in spherical orbits at fixed distances from the nucleas.
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De Broglie's theory states moving particles have some properties of waves.
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Schrodinger develops math equations to describe the motion of electrons.
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Chadwick confirmed the existence of neutrons which have no charge and also stated that atomic nuclei contain neutrons and positively charged protons.
