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  2. Timeline of particle discoveries - Wikipedia

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

    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])

  3. Timeline of atomic and subatomic physics - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_atomic_and...

    The two discovering parties independently assign the discovered meson two different symbols, J and ψ; thus, it becomes formally known as the J/ψ meson. The discovery finally convinces the physics community of the quark model's validity. 1974 Robert J. Buenker and Sigrid D. Peyerimhoff introduce the multireference configuration interaction method.

  4. Timeline of physical chemistry - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_physical_chemistry

    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 ...

  5. Timeline of scientific discoveries - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_scientific...

    1924: Edwin Hubble: the discovery that the Milky Way is just one of many galaxies; 1925: Erwin Schrödinger: Schrödinger equation (Quantum mechanics) 1925: Cecilia Payne-Gaposchkin: Discovery of the composition of the Sun and that hydrogen is the most abundant element in the Universe; 1927: Werner Heisenberg: Uncertainty principle (Quantum ...

  6. History of atomic theory - Wikipedia

    en.wikipedia.org/wiki/History_of_atomic_theory

    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.

  7. History of subatomic physics - Wikipedia

    en.wikipedia.org/wiki/History_of_subatomic_physics

    The electron was discovered between 1879 and 1897 in works of William Crookes, Arthur Schuster, J. J. Thomson, and other physicists; its charge was carefully measured by Robert Andrews Millikan and Harvey Fletcher in their oil drop experiment of 1909.

  8. Periodic trends - Wikipedia

    en.wikipedia.org/wiki/Periodic_trends

    They were discovered by the Russian chemist Dmitri Mendeleev in 1863. Major periodic trends include atomic radius , ionization energy , electron affinity , electronegativity , nucleophilicity , electrophilicity , valency , nuclear charge , and metallic character . [ 1 ]

  9. Timeline of chemistry - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_chemistry

    J. J. Thomson discovers the electron using the cathode ray tube. [82] 1898 Wilhelm Wien demonstrates that canal rays (streams of positive ions) can be deflected by magnetic fields, and that the amount of deflection is proportional to the mass-to-charge ratio. This discovery would lead to the analytical technique known as mass spectrometry. [83 ...