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101
Thales - 620 BC
Was the first person to investigate the basic principle of the atom. -
101
Democritus - 440 BC
He disovered the 1st atomic theory. -
101
Aristotle - 340 BC
He didn't believe in the atomic theory. -
Sir Isaac Newton
He said that atoms are held together by attractions or forces. -
John Dalton
Did the Atomic Theory experiment. Said: 1. All matter is made up at tiny particles called atoms. 2. All atoms of a given element are alike but are different. 3. Compounds are formed when atoms of different elements combine. 4. A chemical reaction involves a rearrangment of atoms, not a change. -
Henri Becquerel
He discovered radioactivity. -
J. J Thompson
Had the Cathode Ray experiment. He discovered electrons by the plum pudding model. -
Robert Milikan
He had the Oil Drop experiment. He found a charge in individual electrons. -
Gold Foil Experiment
Helium nuclei were fired through a thin gold sheet into a zinc sulfide and it proved that part of the atom had a positive charge and that it had mass. -
Ernest Rutherford
His atomic model was The Nuclear Atom. -
Niels Bohr
Theory on electrons and that electrons are on an orbit. -
Francis Aston
In the Mass Spectrograph experiment he found that there was isotopes -
Erwin Schodinger
His experiment was the Quantum Mechanical Model of the Atom. He used math equation to find the probability on election would be in a certain position. -
James Chadwick
He discovered the Neutron.