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Democritus
He named atoms, and believed that they were infinite in number, always moving, could be combined with other atoms, and that each substance has atoms of unique shape and size. He also believed they were indestructable, they're homogeneous, and they differ in size, shape, mass, position, and arrangement. -
John Dalton
He based his theories on experiments, and believed atoms of a given element are identical in mass and property. He also believed that a chemical reaction is a rearrangement of atoms. His model stated that atoms were spheres having their own size. He later proposed the Law of Partial Pressure and his studies led to the Law of Definite Proportions. -
Ernest Rutherford
He was a former student of Rutherford who won the Nobel Prize in Chemistry in 1908. He used gold foil to determine that the postive charge was located in the nucleus of the atom, and that most of the atom is made up of empty space. His model was called a planetary. -
J.J. Thomson
He was an English teacher who created the name "electrons" and found positive and negative parts of atoms. He experimented with the Cathode Ray tube, and created the plum pudding (chocolate chip cookie) model of the atom -
Niels Bohr
He won the 1922 Nobel Prive in Physics. His model was based on mathematics and experimentation -
James Chadwick
Discovered the neutron, the negative part of an atom.
