development of the periodic table

  • Johann Dobereiner

    was born came up with the idea for the table
  • Period: to

    the periodic table progress

    the perodic table has been created by many great science minds.
  • Law of triads

    In 1829 Dobereiner proposed the Law of Triads: Middle element in the triad had atomic weight that was the average of the other two members. Soon other scientists found chemical relationships extended beyond triads.
  • the first elements were descorved

    It was a 19th century geologist who first recognized periodicity in the physical properties of the elements. Alexandre Beguyer de Chancourtois (1820-1886), professor of geology at the School of Mines in Paris, published in 1862 a list of all the known elements.
  • arranging the elements

    John Newlands (1837-1898), having arranged the 62 known elements in order of increasing atomic weights, noted that after interval of eight elements similar physical/chemical properties reappeared.
  • the graet work of Mendeleev

    in 1869, Russian chemist Dimitri Mendeleev (1834-1907) proposed arranging elements by atomic weights and properties (Lothar Meyer independently reached similar conclusion but published results after Mendeleev). Mendeleev's periodic table of 1869 contained 17 columnswith two partial periods of seven elements each (Li-F & Na-Cl) followed by two nearly complete periods (K-Br & Rb-I). his work was so accrute because his table was tried and tested.
  • two new scientst discorved more detail

    Lord Rayleigh (1842-1919) and William Ramsey (1852-1916) greatly enhanced the periodic table by discovering the "inert gases." In 1895 Rayleigh reported the discovery of a new gaseous element named argon. This element was chemically inert and did not fit any of the known periodic groups.
  • by 1900 the whole periodic table had been discovered

    by 1900, the periodic table was taking shape with elements were arranged by atomic weight. For example, 16g oxygen reacts with 40g calcium, 88g strontium, or 137g barium. If oxygen used as the reference, then Ca/Sr/Ba assigned atomic weights of 40, 88, and 137 respectively.