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450
Aristotle (340 BC)
Aristotle Had an idea in which he named "The Four Elements" He believed that all matter was made up of air, water, fire, and earth.
He had no proof for this theory but many people believed him because he was one of the greatest minds of his time. -
Dalton
Dalton said that all matter is made up of atoms and matter cannot be created or destroyed. He also said that a chemical reaction causes a rearrangement of the atoms.
He stated that the protons and neutrons are in the nucleus and electrons are on the outside of the atom. -
Thomson
Discovered the electron.
Atoms are larger bodies of positive charge with negative parts.
Called "Plum Pudding" -
Rutherford
Did the Gold Foil Experiment
Determined there was a large nucleus with an overall positive charge.
Gathered info from an experiment
Called "Rutherford Model" -
Bohr
Discovered protons are in the nucleus.
Electrons can only move in certain paths.
out electrons determine the chemical property.
Called "Bohr Model" -
Heisenberg and Schrodinger
Discovered electron cloud.
Electrons moving fast causes an electron cloud
Built on thoughts of Bohr.
Called "The Cloud Model" -
Democritus
Discovered that all matter is made up of tiny atoms.
Atoms cannot be created or destroyed.
He got thiss idea by observing that no matter how many times you break an object in half, it will never disapear.
