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400 BCE
Democritus
Democritus believed atoms were indivisible, atoms move through the empty space in matter, all atoms are homogeneous, indestructible, and indivisible -
384 BCE
Aristotle
He believed that all atoms were composed of the four basic elements, Earth, Fire, Wind, and Water -
Antoine Lavoisier
Found out that in all chemical reactions, mass is not created or destroyed, it is conserved, this discovery led to the Law of Conservation of Mass -
John Dalton
He states that atoms cannot be created, nor can they be destroyed, this led to the law of conservation of mass -
JJ Thomson
He discovered the electron by working with charges in atoms -
Ernest Rutherford
He discovered the nucleus and that it is a small, + charged particle -
Robert Millikan
Measured charges on electrons in his famous oil drop experiment -
Neil Bohr
concluded that electrons orbit the nucleus in a concentric circle -
Louis DeBroglie
predicted the wave nature of electrons using equations -
Erwin Schrodinger
Used mathematics to predict orbital locations of electrons, concluded there were more electrons in more dense areas of the atom -
Werner Heisenberg
Created the theory of quantum mechanics -
James Chadwick
he found a new particle in the atom, the neutron and that it's charge was neutral
