Dobereiner traids is
Na, K, Rb
Mg, S, As
Cl, Br, I
P, S, As
Dobereiner's triads was a method of classification of elements on the basis of their atomic mass wherein the middle element had an atomic mass which was average of the other two.
Some examples of Dobereiner's triads include (Li,Na, K); (Ca,Sr,Ba); (Cl,Br,I)
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