Dobereiners Triads

  • Dobereiner arranged a group of three elements with similar properties in the order of increasing atomic masses and called it a triad.
  • Dobereiner could identify only the following three triads from the elements known at that time.

 

 

  • He showed that the atomic mass of the middle element is approximately the arithmetic mean of the other two. 

Limitation – He was failed to arrange all known element in the form of triad. And identify only 3 triad from the known element at that time.