Development of the periodic table

By facebooker_100000891496397

  • first periodic table

    Antoine Laviosier drew the first periodic table. This contained 33 different elements.

  • Triads

    in 1817 Johan Dobereiner discovered that stroniums atomic weight falls exactly between the atomic weights of calcium and barium,

  • The Telluric screw

    Alexandre-Emile Béguyer listed the known elements and to a strip of paper and wound them around a cylinder. Groups of 3 elements with similar properties appeared together down the cylinder. This was called the telluric screw

  • Increasing atomic weight

    John Newlands organised the elements in order of increasing atomic weight.

  • 8 intervels

    John Newlands noted down on paper that after each interveal of 8 elements a recurrence of properties appears

  • periodically arranged

    Dimitri Mendeleev made a periodic table in order or atomic weight. But he arranged them periodically so that rows had similar properties, coloumns had similar properties and the diagonally they had similar properties

  • Argon

    Lord Rayleigh discovered Argon

  • Argons positioning

    William Ramsey Suggests that argon gets placed between Chlorine and Potassium dispite the fact that Potassium had a greater atomic weight than Argon

  • Organising by atomic numbers

    Mosely arranged the elements by atomic number rather than atomic mass. This is how it is organised currently.

  • Heavy mass elements

    Glenn Seaborg artificially produces Neptunium which is known as a heavy mass element