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Atomic Theory - Coggle Diagram
Atomic Theory
460-370 BC
Democritus: theorized that the universe is made up of empty space and particles, called atoms. He believed atoms were uniform, solid, hard, and unable to be compressed. He also thought they through empty space until stopped by an outside force, in constant motion through empty space until stopped by an outside force.
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1803
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Dalton: proposed a modern theory of atoms based on these assumptions: all matter is made up of atoms, atoms are indestructible, and all atoms are of an element and are exactly alike but differ from other element's atoms
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1897
Thomson: Through experimenting with a cathode tube, he discovered electrons. He believed that the atom was a sphere and that there were positive and negative charges within it. His model was electrically neutral because it had equal amounts of positive and negative charges. (plum pudding model)
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1911
Rutherford: Discovered the nucleus through experimenting with alpha particles and foil. He decided that all positive charges and most of the mass of the atom had to be found in a very small space within the atom.
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1913
Bohr: Believed that electrons travel in particular orbits around the nucleus, similarly to planets orbiting the sun. He believed that electrons can jump from one orbit to another by emitting or absorbing energy.
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1926
Schrodinger: Discovered that electrons have an intrinsic property called spin, and an electron can either spin-up or spin-down. He also proposed that any two electrons occupying the same area need to have opposite spins. His model treats electrons as matter waves, and brings up the electron cloud.
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