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465 BCE
Democritus
Created the atomic theory of the universe -
John dalton
Developed the first useful atomic theory of matter
Experiments with gases that first became possible at the turn of the nineteenth century -
J.J. Thompson
Discovered the electron
cathode rays produced from the cathode were actually a stream of negatively charged particles called electrons -
Ernest rutherford
Nuclear model of an atom
A beam of alpha particles was aimed at very thin gold foil and their passage through the foil detected -
Niels Bohr
Idea that electrons "jump" between energy levels
which depicts the atom as a small, positively-charged nucleus surrounded by negatively-charged electrons that travel in circular orbits around the nucleus
