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Democritus' concept of the atom
Democritus proposed the existence of atoms.
Limited technology at the time meant this was just an idea and could not be tested. -
Dalton's atomic theory
Dalton developed his theory of atoms and matter.
Experiments in chemistry and careful measurement of results allowed Dalton to support his hypothesis with evidence. -
plum pudding
JJ Thomson discovered the electron.
Experiment using electric charges in cathode ray tubes. -
Rutherford's planetary model
Rutherford developed the planetary model of the atom.
Experiment using alpha particles fired at thin gold foil and an early prototype Geiger counter to measure results. -
Bohr's model
Bohr developed a model of the atom.
Bohr used mathematical models and laws of quantum physics to propose his updated model. -
Chadwick- bohr model
The neutron was discovered by James Chadwick.
Experiments using kinematics and accurate measurements lead to proving the existence of a previously undetected subatomic particle, the neutron.
