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…showed last 75 words of 424 total…assify all of the atoms, both natural and man made, by their atomic number (that is to say the number of protons that they contain). Then in 1897, Thompson discovered the first component part of the atom: the electron, a particle with a negative electric charge. In 1904, he proposed an initial model of an atom, since nicknamed "Thompsons pudding". He imagined the atom as a sphere full of an electrically positive substance mixed with negative electron.