Dobereiner traids is

If the sum of atomic mass of 3 elements forming Dobereiner traid is 69, then atomic mass of second element

Dobereiner triad is

Which of the following is Dobereiner traid :

Did Dobereiner's traids also exist in the columns of Newlands's Octaves ? Compare and find out.

Example of Dobereiner's triad is ___

The element M in the Dobereiner traid: S,M,Te is