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Democritus - 400BC
Proposed that matter was composed of iny indivisible particles called atomos. -
John Dalton
Proposed "billiard Ball' model- atom is a unifrom soild sphere. -
JJ Thompson
Proposed "Plum Pudding" model- atom has a postive sphere (pudding) with negative electrons (plums) dispersed throughtout. -
Ernest Rutherford
Discovered nucleus of atoms. Proposed 'Nuclear' model- atom has dense, postive nucleus surrounded by negative electrons. -
Niels Bohr
Propsed "planetary' nodel- atom has electrons that move in circular orbits within specific energy levels. -
James Chadwick
Revised 'Nuclear' model- atom has a neutral particles in the nucleus (neutrons).
