Question

Write any one triad of Dobereiner. List the factors he considered for such aclassification.

Answer 1

Lithium, Sodium, Potassium
Chlorine, Bromine, Iodine are two triads given by Dobereiner.
He tried to correlate the properties of the elements with their atomic weight.
He listed the factor that the triads of elements showed similar chemical properties. He said that the atomic weight of the middle element was the arithmetic mean of the other two elements. He also said that other properties of the elements listed in the triads also followed the same trend as atomic weight, i.e. the value of the middle element of the triad was in between the other two end members.