Peiodic table pic

Development of the Periodic Table

By Rachel Key

  • The periodic table begins.

    He grouped elements based on similarities.Calcium, strontium , and barium possess similar chemical prepares. Dobereiner noticed the atomic weight of strontium fell midway between the weights of calcium and barium.

  • Dobereiner proposed the Law of Triads

  • Lithium, Sodium, and Potassium provided evidence for the law of Triads

  • John Dobereiner died

  • 60 elements had been discovered.

    60 elements had been discovered.

  • John Newlands wrote a paper proposing the Law of Octaves.

    John Newlands wrote a paper proposing the Law of Octaves.
    The law is - Elements exhibit similar behavior to the eighth element following it in the table.

  • Mandeleev arranged elements by atomic weigh and properties independently reaching similar conclusions.

    Mandeleev arranged elements by atomic weigh and properties independently reaching similar conclusions.

  • Mandeleev revised the 17-group table with 8 colums.

    Mandeleev revised the 17-group table with 8 colums.

  • The Proton was discovered.

    The Proton was discovered.
    Rutherford's landmark experiment discovered the proton.

  • Moseley used x-rays to find relationships between x-ray frequency and number of protons.

    Moseley used x-rays to find relationships between x-ray frequency and number of protons.
    (not sure exact date so i juat made a guess)

  • Elements 94 to 100 were discovered by Seaborg.

    Elements 94 to 100 were discovered by Seaborg.