determined by the properties of these particles. This core theory was then modified and altered over years by Dalton, Thompson, Rutherford, Bhor, and Chadwick. The atoms original structure was simple, but as more and more research was done the atom became more complex and puzzling.

Our first benefactor of atomic theory was John Dalton, a man later nick-named the "Father of atomic theory" for his contribution of many theories and laws to modern atomic theory. His theories answered many questions of skeptical scientists: elements combine with one another to form chemical compounds and the atom doesn't change, atoms link together in definite proportions, all atoms of any element are all the same, the law of multiple p

Chadwick discovered the last piece of information about the atom. In 1932, through mass spectronomy, he discovered a heavy neutral particle with the mass of a proton. He called it a neutron. This answered the few remaining question about the atom. There was no longer a missing part because the neutron made up for the original weight loss. And it answered the question about how the protons stayed together. The neutrons had a soothing effect on the protons. Between every two protons lies a neutron, which attracted the protons, which made the nucleus very condensed.

Ernest Rutherford was a major contributor to the atomic model because he proved that although Dalton and Thompson were partially correct there was still a flaw in both of their models of the atom. Rutherford devised an experiment to either prove or disprove Dalton's model and or Thompson's model. Rutherford and his assistants put a piece of radioactive material in a lead box with a small hole in one side to direct the alpha particles towards the gold foil, which was surrounded by zinc sulfide screens. The zinc screens showed flashes of light where the alpha particles were going to go, straight through (Thompson's model) or straight back (Dalton's model). To his astonishment particles were through, came back, and some also were deflected to the sides of the gold foil. He proved that Dalton and Thompson were incorrect and the atom consisted mostly of space. At the center of this space is a very small core, called the nucleus, which can justify the deflected particles. Rutherford established that the mass of the atom is concentrated in its nucleus. He found that an electron is 1/1836 the mass of a proton and he also proposed that electrons travel in orbits around the nucleus.

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