J. J. Thomson’s “Plum-pudding” Model

• After its discovery, the electron was assumed to be a part of the atom.

• Thomson proposed positive charge was spherically distributed.

• Electrons radiated as they oscillated within this positive pudding.

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Thompson explained emission lines by assuming his electrons were trapped in a continuous blob of positive charge, like negative plums in a positive pudding. However, there was no way he could explain the precise wavelength patterns emitted by particular elements.