Atomic Theory Timeline
Category: Other
Updated: 25 Sep 2018
By: John Alacce, Tim Owen
Sources:
https://en.wikipedia.org/wiki/Timeline_of_atomic_and_subatomic_physics
https://www.google.com/search?q=when+was+the+periodic+table+created&rlz=1CADEAC_enUS815&oq=when+was+the+peri&aqs=chrome.1.69i57j0l5.6183j1j7&sourceid=chrome&ie=UTF-8&safe=active&ssui=on
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Created byJohn Alacce
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Events
450B.C empedocles proposes that all things are made of 4 elements, earth, water, fire, and air, where opposing forces act upon these elements, combining and separating them into varied forms.440B.C leucippus and democritus propose the idea of an atom, and indivisable particle that all things are made of360B.C plato uses the term elements for the first time, and states that each element has a different geometric shape, earth(cube), fire(tetrahedron), air(octahedron), water(icosahedron)1805C.E Joseph Louis Gay-Lussac discovers that water is composed of two parts hydrogen and one part oxygen by volume.1811C.E Amedio Avogadro claims that equal volumes of gas should contain equal numbers of molecules1832C.E Michael Faraday states laws of electrolysis1848C.E Lord Kelvin establishes the concept of absolute zero where all molecular motion ceases1865C.E Johann Josef Loschmidt determines exact number of molecules in a mole, later named Avogadro's number.1869C.E Dmitri Mendeleyev creates the periodic table1871C.E Dmitri Mendeleyev examines the periodic table and predicts the existence of gallium, scandium, and germanium1873C.E Johannes van der Waals proposes the idea of weak attractive forces between molecules1877C.E Ludwig Boltzmann establishes statistical deviations of important physical and chemical substances such as entropy and distributions of molecular velocities in the gas phase1883C.E Svante Arrhenius develops ion theory to explain conductivity in electrolytes1894-1898C.E William Ramsay discovers the noble gases, which fill a large and unexpected gap in the periodic table and led to models of chemical bonding.1897C.E J.J. Thompson discovers the electron using the cathode ray tube1900C.E Ernest Rutherford discovers the source of radioactivity as decaying atoms; coins terms for various types of radiation.1904C.E hantaro nagaoka proposes an early nuclear model of the atom where electrons orbit a dense nucleus1905C.E Albert Einstein explains brownian motion, proving atomic theory1909C.E S. P. L. Sørensen Invents the pH concept and develops methods to measure acidity1913C.E Niels Bohr introduces concepts of quantum mechanics to atomic structure by proposing what is now known as the Bohr model of the atom, where electrons exist only in strictly defined orbitals.1913C.E Frederick Soddy proposes the concept of isotopes, that elements with the same properties could have different weights1923C.E Gilbert N. Lewis develops the electron pair theory of acid/base reactions1927C.E Fritz London and Walter Heitler apply quantum mechanics to explain covalent bonding in the hydrogen molecule, which marked the birth of quantum chemistry.1932C.E James Chadwick discovers the neutron.1932-1934C.E Linus Pauling and Robert Mulliken quantify electronegativity, devising the scales that now bear their names.1934C.E Enrico Fermi suggests bombarding uranium atoms with neutrons to make a 93 proton element1938C.E Otto Hahn discovers the process of nuclear fission in uranium and thorium.1939C.E Linus Pauling publishes The Nature of the Chemical Bond, a compilation of a decades worth of work on chemical bonding. It is one of the most important modern chemical texts. It explains hybridization theory, covalent bonding and ionic bonding as explained through electronegativity, and resonance as a means to explain, among other things, the structure of benzene.1941C.E Glenn T. Seaborg takes over McMillan's work creating new atomic nuclei. Pioneers method of neutron capture and later through other nuclear reactions. Would become the principal or co-discoverer of nine new chemical elements, and dozens of new isotopes of existing elements.1942C.E Enrico Fermi makes the first controlled nuclear chain reaction1945C.E Jacob A. Marinsky, Lawrence E. Glendenin, and Charles D. Coryell perform the first confirmed synthesis of Promethium, filling in the last "gap" in the periodic table1953C.E James D. Watson and Francis Crick propose the structure of DNA, opening the door to the field of molecular biology.1957C.E Jens Skou discovers Na⁺/K⁺-ATPase, the first ion-transporting enzyme.1962C.E Neil Bartlett synthesizes xenon hexafluoroplatinate, showing for the first time that the noble gases can form chemical compounds.1995C.E Eric Cornell and Carl Wieman produce the first Bose–Einstein condensate, a substance that displays quantum mechanical properties on the macroscopic scale.1998C.ESuper-Kamiokande (Japan) observes evidence for neutrino oscillations, implying that at least one neutrino has mass.2008C.E The Large Hadron Collider at CERN is scheduled to begin operation in this year. Its primary goal is to search for the Higgs boson, which had not been found yet.2012C.E CERN announces the discovery of a new particle with properties consistent with the Higgs boson of the Standard Model after experiments at the Large Hadron Collider.600B.C Kanada theorized the existence of 4 types of atoms which can combine into diatomic and triatomic particles770C.E Abu Musa Jabir Ibn Hayyan a persian alchemist who is called the father of chemistry, develops an early scientific method for chemistry.1000C.E Abū al-Rayhān al-Bīrūnī and avicenna, persian chemists refute the theory of transmutation of metals1267C.E Roger bacon writes Opus Maius which contains an early form of the scientific method.1615C.E Jean Beguin publishes the Tyrocinium Chymicum which contains the first chemical equation1662C.E Robert Boyle proposes boyle’s law, an experimentally based description on the behavior of gases1754C.E Joseph Black isolates carbon dioxide for the first time which he calls “fixed air”1766 C.E henry cavendish discovered hydrogen1778C.E Carl Scheele and antoine lavoisier discover that air is mostly hydrogen and nitrogen1781C.E Joseph Priestley creates water by igniting hydrogen and oxygen1800C.E william nicholson and Anthony Carlisle use electrolysis to separate hydrogen and oxygen1803C.E John Dalton introduces atomic ideas and states that atoms have different weightsPeriods
Atomic Theroy Timeline
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