Question

What was the basis of Dobereiner's classification of the elements ?

Answer 1

1. Dobereiner triad: The elements with similar physical and chemical properties are arranged in a set of three elements where the atomic mass of second element is the average of atomic masses of first and third element.
2. Example: Li(7), Na(23), K(39)

$\frac{7+39}{2}=\frac{46}{2}=23$

Therefore , the basis of Dobereiner's classification of the elements is Atomic mass.