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  2. Plum pudding model - Wikipedia

    en.wikipedia.org/wiki/Plum_pudding_model

    An atom with seven electrons arranged in a pentagonal dipyramid, as imagined by Thomson in 1905. The plum pudding model is an obsolete scientific model of the atom.It was first proposed by J. J. Thomson in 1904 following his discovery of the electron in 1897, and was rendered obsolete by Ernest Rutherford's discovery of the atomic nucleus in 1911.

  3. Thomson problem - Wikipedia

    en.wikipedia.org/wiki/Thomson_problem

    The Thomson problem is a natural consequence of J. J. Thomson's plum pudding model in the absence of its uniform positive background charge. [ 12 ] "No fact discovered about the atom can be trivial, nor fail to accelerate the progress of physical science, for the greater part of natural philosophy is the outcome of the structure and mechanism ...

  4. J. J. Thomson - Wikipedia

    en.wikipedia.org/wiki/J._J._Thomson

    Plaque commemorating J. J. Thomson's discovery of the electron outside the old Cavendish Laboratory in Cambridge Autochrome portrait by Georges Chevalier, 1923 Thomson c. 1920–1925 Thomson was elected a Fellow of the Royal Society (FRS) [ 24 ] [ 49 ] and appointed to the Cavendish Professorship of Experimental Physics at the Cavendish ...

  5. Rutherford scattering experiments - Wikipedia

    en.wikipedia.org/wiki/Rutherford_scattering...

    The prevailing model of atomic structure before Rutherford's experiments was devised by J. J. Thomson. [2]: 123 Thomson had discovered the electron through his work on cathode rays [3] and proposed that they existed within atoms, and an electric current is electrons hopping from one atom to an adjacent one in a series.

  6. Bohr model - Wikipedia

    en.wikipedia.org/wiki/Bohr_model

    When Bohr began his work on a new atomic theory in the summer of 1912 [8]: 237 the atomic model proposed by J J Thomson, now known as the Plum pudding model, was the best available. [9]: 37 Thomson proposed a model with electrons rotating in coplanar rings within an atomic-sized, positively-charged, spherical volume. Thomson showed that this ...

  7. Rutherford model - Wikipedia

    en.wikipedia.org/wiki/Rutherford_model

    The Rutherford model is a name for the first model of an atom with a compact nucleus. The concept arose from Ernest Rutherford discovery of the nucleus. Rutherford directed the Geiger–Marsden experiment in 1909, which showed much more alpha particle recoil than J. J. Thomson's plum pudding model of the atom could explain. Thomson's model had ...

  8. Cathode ray - Wikipedia

    en.wikipedia.org/wiki/Cathode_ray

    The debate was resolved in 1897 when J. J. Thomson measured the mass of cathode rays, showing they were made of particles, but were around 1800 times lighter than the lightest atom, hydrogen. Therefore, they were not atoms, but a new particle, the first subatomic particle to be discovered, which he originally called " corpuscle " but was later ...

  9. Timeline of particle discoveries - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_particle...

    Electron discovered by J. J. Thomson [4] 1899 Alpha particle discovered by Ernest Rutherford in uranium radiation [5] 1900 Gamma ray (a high-energy photon) discovered by Paul Villard in uranium decay [6] 1911 Atomic nucleus identified by Ernest Rutherford, based on scattering observed by Hans Geiger and Ernest Marsden [7] 1919