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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 ...
1897 J. J. Thomson discovered the electron; 1897 Emil Wiechert, Walter Kaufmann and J.J. Thomson discover the electron; 1898 Marie and Pierre Curie discovered the existence of the radioactive elements radium and polonium in their research of pitchblende; 1898 William Ramsay and Morris Travers discover neon, and negatively charged beta particles
1932 Antielectron (or positron), the first antiparticle, discovered by Carl D. Anderson [13] (proposed by Paul Dirac in 1927 and by Ettore Majorana in 1928) : 1937 Muon (or mu lepton) discovered by Seth Neddermeyer, Carl D. Anderson, J.C. Street, and E.C. Stevenson, using cloud chamber measurements of cosmic rays [14] (it was mistaken for the pion until 1947 [15])
Atoms were thought to be the smallest possible division of matter until 1899 when J. J. Thomson discovered the electron through his work on cathode rays. [37]: 86 [5]: 364 A Crookes tube is a sealed glass container in which two electrodes are separated by a vacuum.
This is given by λ e = h/p where h is the Planck constant and p is the momentum. [60] For the 51 GeV electron above, the wavelength is about 2.4 × 10 −17 m, small enough to explore structures well below the size of an atomic nucleus. [147]
Some particles including the positron were even discovered by using this device. By 1914, experiments by Ernest Rutherford, Henry Moseley, James Franck and Gustav Hertz had largely established the structure of an atom as a dense nucleus of positive charge surrounded by lower-mass electrons. [6]
This discovery of the wave–particle duality of matter and energy was fundamental to the later development of quantum field theory. 1909 and 1916: Albert Einstein: Showed that, if Planck's law of black-body radiation is accepted, the energy quanta must also carry momentum p = h / λ, making them fully fledged particles, albeit with no "rest ...
He predicts that the wavelengths are given by the Planck constant h divided by the momentum of the mv = p of the electron: λ = h / mv = h / p. [1] Gilbert N. Lewis creates the theory of Lewis acids and bases based on the properties of electrons in molecules, defining an acid as accepting an electron lone pair from a base.