HISTORY OF PERIODIC TABLE

       HISTORY of

  PERIODIC  TABLE

1817

Johann Wolfgang Döbereiner

Döbereiner

 In 1817 a German scientist Dobereiner suggested that properties of elements 

are related to their atomic masses. He made groups of three elements each, having similar 

chemical properties and called them triads. He arranged the three elements in a triad in an 

increasing order of atomic mass and showed that the atomic mass of the middle element 

was approximately equal to the mean of the atomic masses of the other two elements. 

However, all the known elements could not be classified into the Dobereiner’s triads.