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430 BCE
Democritus
He believed that atoms are constantly moving, atoms are "uncuttable" and they are small, hard practice particles. -
Dalton
Dalton conducted experiments by combining elements, discovered atoms of different elements are different, stated all substance are made of atoms, and elements combined in specific proportions -
J.J.Thomas
Thomas created the plum pudding, found they are small, negatively charged particles inside an atom and conducted the cathode-ray tube experiment -
Ernest Rutherford
Rutherford conducted the gold foil experiment, discovered there is a small, dense, positively charged nucleus and stated atoms mostly contain empty space and most of atom's mass is in the nucleus -
Niels Bohr
Bohr discovered electrons jump between levels from path to path, they also move in the empty space of an atom and they travel in definite paths -
Erwin Schrodinger and Werner Heisenberg
They discovered electron paths cannot be predicted and electron are found in clouds, not paths,
