This is the Plum Pudding Model. It was developed by JJ Thompson. He proposed this because of the Cathode ray experiments that he completed in the 1890s. These experiments proved the existence of negatively-charged particles associated with electrons. The Plum Pudding Model suggests negatively charged particles embedded in a ball of positive charges.
Physical Science: 4.1 The Development of Atomic TheoryPowerPoint Presentation (4.1 of 18.3)* Unit 2*This is part of a series based upon chapters and sectionsTopics: Democritus, atoms, John Dalton, Law of Definite Proportions, J.J. Thomson, Plum Pudding model, electrons, Ernest Rutherford, gold-foil experiment, nucleus, protons, neutrons, Niels Bohr, electron energy levels, modern wave model
On April 30, 1897, English physicist Joseph John Thomson gives the first experimental proof of the electron, which had been already theoretically predicted by Johnstone Stoney. Thomson was awarded the 1906 Nobel Prize in Physics for the discovery of the electron and for his work on the conduction of electricity in gases.