Current periodic table

Development of the Periodic Table

By stebbni
  • Johann Dobereiner proposes the Law of Triads

    Johann Dobereiner proposes the Law of Triads

    The middle element in the triad has atomic weight that is the average of the other two members.
  • Alexandre Beguyer de Chancourtois publishes a list of all the known elements

    Alexandre Beguyer de Chancourtois publishes a list of all the known elements

    The list was constructed as a helical graph wrapped around a cylinder-elements with similar properties occupied positions on the same vertical line of cylinder (the list also included some ions and compounds).
  • John Newlands writes a paper proposing The Law of Octaves

    John Newlands writes a paper proposing The Law of Octaves

    Elements exhibit similar behavior to the eighth element following it in the table.
  • Dimitri Mendeleev proposes arranging elements by atomic weights and properties

    Dimitri Mendeleev proposes arranging elements by atomic weights and properties

    Mendeleev's periodic table contained 17 columns with two partial periods of seven elements each followed by two nearly complete periods.
  • Henry Moseley derives the relationship between x-ray frequency and the number of protons in elements

    Henry Moseley derives the relationship between x-ray frequency and the number of protons in elements

    Through this he arranged the elements according to increasing atomic numbers and not atomic masses and subsequently some of the inconsistencies associated with Mendeleev's table were eliminated.
  • Glenn Seaborg discovers the transuranium elements and reconfingures the periodic table

    Glenn Seaborg discovers the transuranium elements and reconfingures the periodic table

    He did so placing the lanthanide/actinide series at the bottom of the table.