A group of three elements in which atomic weight of middle element is average of first and third element is called Dobereiner triad.
Eg : 1) Li, Na, K 2) Cl, Br, I
A group of three elements in which atomic weight of middle element is average of first and third element is called Dobereiner triad.
Eg : 1) Li, Na, K 2) Cl, Br, I