1829 Johann Dobereiner discovered the halogen triad and the alkali metal triad.
1862I, A.E. Beguyer de Chancourtois assembled the table by transcribing a list of the elements positioned on a cylinder in terms of increasing atomic weight, It was the first periodic table ever was created
1869 - Newlands published his version of the periodic table and proposed the Law of Octaves (by analogy with the seven intervals of the musical scale).
1869- Russian Dmitri Mendeleev published his periodic table, eventually becoming the “father of the periodic table.”