Summary Of Atomic Models After John Dalton's postulations of the Atomic Theory, several scientists carried out investigations on the structure of the atom to either validate or disapprove the theory. This eventually led to its modifications, as only one out of the five postulations made by Dalton was and is still valid, i.e., all chemical changes result from the combination or the separation of atoms . The results of the major studies of are summarized below: J . J . Thompson Using his discharge tube and cathode rays experiments, he discovered that an atom is made up of positively charged particles called protons, and negatively charged particles called electrons. He went on to propose that the atom is a sphere of positively charged matter in which negatively charged electrons are embedded . His model looks like an orange filled with seeds. Ernest Rutherford Through his gold-foil experiment, he proposed that the atom is made up of a positive core...
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