Perioditic Table history

  • First element discovered

    1649 is when the first element was discovered through scientific inquiry by Hennig Brand.
  • Isaac Newton

    Proposed a mechanical universe with small soild masses in motion
  • John Dalton

    Proposed an "atomic theory" with spherical soild atoms based upon measurable properties of mass
  • A.E. Beguyer de Chancourtois first to use atomic weight

    A.E. Beguyer de Chancourtois was the first person to use the atomic weights to reveal the elements is arranged according at regular intervals. He drew the elements on a spiral around a cylinder divided into 16 parts. The elements list was wrapped around a cylinder so that the similar was lined up, making a geometric representation of the periodic table.
  • Halogen was discovered

    Johann Dobereiner had discovered the halogen triad made up of chlorine, bromine, and iodine and a alkali metal triad of lithium, sodium and potassium un the year 1829.
  • Michael Faraday

    Studied the effect of electricity on solutions, coined term "electrolysis" as a splitting of molecules with electricity, developed laws of electrolysis. Faraday himself was not a proponent of atomism.
  • John Newlands law: November 29,1837- July 29,1898

    John Newlands, an English chemist, afford the Law of Octaves that started the elements repeated their chemical properties every 8th element in 1863
  • J. Plucker

    Built one of the first gas discharge tubes ("cathode ray tube").
  • Meyer made a long table

    Meyer constructed an long table which he gave to a colleague for evaluation in 1863.
  • Dmitiri Mendeleev

    The 63 elements has discovered in 1869.
  • The fathers of the Periodic Table

    The Fathers of the Periodic Table is Lothar Meyer and Dmitri Ivanovich Mendeleev. They independently prouduced similar versions of the periodic table. 1864 textbooks included an abbreviated version of a periodic table made for using to classify about half of the known elements.
  • Dmitri Mendeleev

    Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law.
  • table released

    The table wasn’t released until 1870; a year after Mendeleev’s tables came out. Mendeleev’s table appeared in his work “On the Relationship of the Properties of the Elements to their Atomic Weights
  • James Clerk Maxwell

    Proposed electric and magnetic fields filled the void.
  • Sir Willam Crookes

    Discovered cathode rays had the following properties: travel in straight lines from the cathode; cause glass to fluoresce; impart a negative charge to objects they strike; are deflected by electric fields and magnets to suggest a negative charge; cause pinwheels in their path to spin indicating they have mass.
  • E. Goldstein

    Used a CRT to study "canal rays" which had electrical and magnetic properties opposite of an electron.
  • radioactivity

    1886 French physicist Antoine Bequerel first discovered radioactivity. Thomson student from New Zealand Ernest Rutherford named three types of radiation; alpha, beta and gamma rays. Marie and Pierre Curie started working on the radiation of uranium and thorium, and subsequently discovered radium and polonium. They discovered that beta particles were negatively charged.
  • G.J. Stoney

    Proposed that electricity was made of discrete negative particles he called electrons ".
  • Wilhelm Roentgen

    Using a CRT he observed that nearby chemicals glowed. Further experiments found very penetrating rays coming from the CRT that were not deflected by a magnetic field. He named them "X-rays".
  • Henri Becquerel

    While studying the effect of x-rays on photographic film, he discovered some chemicals spontaneously decompose and give off very pentrating rays.
  • J.J. Thomson

    Used a CRT to experimentally determine the charge to mass ratio (e/m) of an electron =1.759 x 10 8 coulombs/gram.
  • J.J. Thomson

    Used a CRT to experimentally determine the charge to mass ratio (e/m) of an electron =1.759 x 10 8 coulombs/gram.
  • Marie Sklodowska Curie

    Studied uranium and thorium and called their spontaneous decay process "radioactivity". She and her husband Pierre also discovered the radioactive elements polonium and radium.
  • Rutherford

    Studied radiations emitted from uranium and thorium and named them alpha and beta.
  • Soddy

    Observed spontaneous disintegration of radioactive elements into variants he called "isotopes" or totally new elements, discovered "half-life", made initial calculations on energy released during decay.
  • Max Planck

    used the idea of quanta (discrete units of energy) to explain hot glowing matter.
  • Rutherford

    In 1903 Rutherford announced that radioactivity is caused by the breakdown of atoms.
  • Nagaoka

    Postulated a "Saturnian" model of the atom with flat rings of electrons revolving around a positively charged particle.
  • Abegg

    Discovered that inert gases had a stable electron configuration which lead to their chemical inactivity.
  • Albert Einstein

    Published the famous equation E=mc 2
  • Hans Geiger

    Developed an electrical device to "click" when hit with alpha particles.
  • R.A. Millikan

    Oil drop experiment determined the charge (e=1.602 x 10 -19 coulomb) and the mass (m = 9.11 x 10 -28 gram) of an electron.
  • Ernest Rutherford

    Using alpha particles as atomic bullets, probed the atoms in a piece of thin (0.00006 cm) gold foil . He established that the nucleus was: very dense,very small and positively charged. He also assumed that the electrons were located outside the nucleus.
  • Rutherford and Hans Geiger

    In 1911 Rutherford and German physicist Hans Geiger discovered that electrons orbit the nucleus of an atom.
  • Bohr

    In 1913 Bohr discovered that electrons move around a nucleus in discrete energy called orbitals. Radiation is emitted during movement from one orbital to another.
  • Henry Moseley

    Through his work with X-rays, he determined the actual nuclear charge (atomic number) of the elements*. He rearranged the elements in order of increasing atomic number.
  • Ruthford 1914

    In 1914 Rutherford first identified protons in the atomic nucleus. He also transmutated a nitrogen atom into an oxygen atom for the first time. English physicist Henry Moseley provided atomic numbers, based on the number of electrons in an atom, rather than based on atomic mass
  • H.G.J. Moseley

    Using x-ray tubes, determined the charges on the nuclei of most atoms. He wrote"The atomic number of an element is equal to the number of protons in the nucleus". This work was used to reorganize the periodic table based upon atomic number instead of atomic mass.
  • Aston

    Discovered the existence of isotopes through the use of a mass spectrograph
  • Niels Bohr

    Developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons.
  • de Broglie

    Discovered that electrons had a dual nature-similar to both particles and waves. Particle/wave duality. Supported Einstein.
  • Heisenberg

    Described atoms by means of formula connected to the frequencies of spectral lines. Proposed Principle of Indeterminancy - you can not know both the position and velocity of a particle.
  • Cockcroft/ Walton

    Built an early linear accelerator and bombarded lithium with protons to produce alpha particles
  • Schrodinger

    Viewed electrons as continuous clouds and introduced "waved mechanics" as a mathematical model of the atom.
  • Paul Dirac

    Proposed anti-particles . Anderson discovered the anti-electron (positron) in 1932 and Segre/Chamberlain detected the anti-proton in 1955..
  • James Chadwick

    Using alpha particles discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.
  • James Chadwick

    In 1932 James Chadwick first discovered neutrons, and isotopes were identified. This was the complete basis for the periodic table. In that same year Englishman Cockroft and the Irishman Walton first split an atom by bombarding lithium in a particle accelerator, changing it to two helium nuclei.
  • Lise Meitner- Hann, Strassman

    Conducted experiments using heavy elements to capture neutrons and form unstable products which undergo fission.
  • Glenn Seaborg

    Synthesized 6 transuranium elements and suggested a change in the layout of the periodic table.
  • Enrico Fermi

    Conducted the first controlled chain reaction releasing energy from the atoms nucleus.
  • Glenn T. Seaborg

    He moved 14 elements out of the main body of the periodic table to their current location below the Lanthanide series. The 14 elements moved are now called the Actinide Series.
  • Glenn Seaborg

    In 1945 Glenn Seaborg identified lanthanides and actinides (atomic number >92), which are usually placed below the periodic table.
  • Greek era: Democritus

    "by convention bitter, by convention sweet, but in reality atoms and void"
  • Mendeleev's table appeared

    .Mendeleev’s table appeared in his work “On the Relationship of the Properties of the Elements to their Atomic Weights. Glenn Seaborg discovered the transuranium elements and atomic numbers 94 to 102.