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450
Democritus
Democritus(430bc). He discovered that all matter is made up of microscopic things called particles. He dicovered this by noticing elements .He believed you could break matter until it couldnt be broken any more. -
450
Aristotle
Aristotle (430B.C.) he argued with Democritus that matter is uniform throughout. -
Dalton
Dalton (1766) proposed an atomic theory where elements are composed of atoms. Atoms are also of different size. He used different gasses to discover atoms. -
Thompson
Thompson concluded that atoms contained small negatively charged particles embedded in a positively charged mass. He bounced cathode rays off of atoms to find the electrons -
Rutherford
Rutherford (1911) proposed that most mass of an atom is retained in the center of the atom and the center is positively charged. He came to this conclusion by conducting the gold foil expierment to discoverthe angles and speed that the atoms deflected off of the foil -
Bohr
Bohr (1913) proposed energy levels to explain the spectrum of hydrogen. He created quantum physics to come up with energy levels. -
Heisenburg and Shrodinger
They concluded that electrons dont follow specific paths or orbits but tend to appeare more oftenly in a given area around the nuclues at a given time. They proposed the heisenburg uncertanty principle
