The 
Plum pudding model of the atom was made after the discovery of the 
electron but before the discovery of the 
proton or 
neutron. In it, the atom is envisioned as electrons surrounded by a soup of positive charge, like 
plums surrounded by 
pudding. This model was disproved by an experiment by 
Ernest Rutherford when he discovered the nucleus of the atom.
See also: Rutherford scattering, atom
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