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Formulated the atomic theory of the universe. Alive in 460 B.C.
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Developed of of Democritus's theories, Dalton devloped his own atomic theory which is still validated today.
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Discovered that cathode rays were composed o f a previously unknown negatively charged particle. He discovered the electron, and was the first to find a subatomic particle.
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DIscovered the concept of radioctive half-life.
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Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete, and that the electrons revolve in stable orbits around the atomic nucleus, but can jump from one energy level (or orbit) to another.
