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450
Democritus (450BC)
Democritus stated the world consists of atoms that moves; they can't be seen or destroyed; differ from one another in size, shape, and position. -
Dalton
Dalton said that all elements consisted pf tiny particles called atoms. His atomic thoery stated general information on the atom. For example it stated that most of the mass of atoms comes from the neuclus. -
Thomson
Thomson discovered electrons. He believed the rings around the atom were pieces pf matter. He thought he say little rays going around the nuelus (they were really electrons). -
Rutherford
Rutherford was the first person to break up the nucleus of the atom. He is also known as the Father of Nuclear Science. He also stated that there was a lot of apce between the nucleus and the electrons. First person to break up the nucleus into protons and nuetrons. -
Bohr
Bohr discovered that electrons orbit the nueclus , energy proportionate to all distances from nucleus (more distance=more energy), orbits are quatized, light absorbed when an electron jumps to higher orbit and omitted when an electronfalls into lower orbit, and the energy of light emittes or absorbed equals to different energies of the orbits. -
Heisenburg and Schrodinger
Heinsburg and Scrodinger stated that nuclei are made up of neutrons and protons, not protons and electrons. They were also the first sciencetists to indtroduce the electron cloud. -
Citations
Leeper, Angela. "Ernest Rutherford and the Birth of the Atomic Age/John Dalton and the Development of Atomic Theory." EBSCO. Student Research Center, n.d. Web. Downey, Ed. "Democritus." EBSCO. Student Research Center, n.d. Web. Crepeau, Bob. "Niels Bohr." EBSCO. Student Research Center, n.d. Web. Comlumbia Electronic Encyclopedia, 6th Edition. "John Dalton." EBSCO. Student Research Center, n.d. Web. Columbia Electronic Encyclopedia, 6th Edition. "Sir Joseph John Thomson." EBSCO. Student R -
Aristotle (348BC)
Aristotle believed that all matter was made of "The Four Elements" which are Fire, Water, Air, and Earth. He did not have any proof and neither did the Atomic Theory. Although, people believed him because at the time, Aristotle was one of the greatest minds.
