... Chadwick and Niels Bohr. First in 1808, John Dalton came up with the Atomic Theory. He believed that atoms were the smallest particle of matter that could take place in a reaction. He also believed that they were indivisible and could not be created or destroyed. Then in 1897, J. J. Thomson discovered the electron. He found them to be tiny, negatively charged particles. He did this by conducting experiments with Cathode Ray Tubes (CRT). This led him to believe that atoms were divisible. A year later (1898) he came up with the "plum pudding" model of the atom, which showed electrons being fixed in a positively charged sphere. 2 years later, in 1900, E. Goldstein discovered the proton. He did this by conducting Anode Ray Experiments. He believed that since atoms had an overall neutral charge, they had to contain positive particles (protons) to balance the charges of the electrons. In the ...

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