Thomson's model of the atom After the electron was discovered by J.J. Thomson in 1897, people realized that atoms were made up of even smaller particles than they had previously thought. However, the atomic nucleus had not been discovered yet and so the “plum pudding model” was put forward in 1904. In this model, the atom is made up of negative electrons that float in a “soup” of positive charge, much like plums in a pudding or raisins in a fruit cake. (0h 42min, jan 24, 1904 y – jan 1, 1911)
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0h 42min, jan 24, 1904 y
jan 1, 1911
~ 6 years and 11 months