Question

What are dobereiners triads?

Answer 1

Doberiner in 1817 observed that certain elements, which had similar chemical properties, could be grouped together. When these elements were arranged in increasing order of their atomic masses, they generally occurred in groups of three. These groups were called triads. He noticed that the atomic mass of the middle element of the triad was the arithmetic mean of the other two elements. This was known as the Dobereiner’s law of triads. The law states that: when elements are placed in order of the ascending order of atomic masses, groups of three elements having similar properties are obtained. The atomic mass of the middle element of the triad is equal to the mean of the atomic masses of the other two elements of the triad.