The dobereiner triads represent one of the first experiments that were carried out to classify chemical elements, depending on the similarity in their characteristics, associating them with their atomic weights. The chemist Johann Dobereiner was the attempt to classify chemical elements, depending on the similarity of their characteristics by linking their atomic weights.
Johann Dobereiner was a German scientist who discovered a certain connection between the characteristics of some groups of elements, for example the atomic mass of lithium and potassium were very close to that of sodium and the same happened with other elements. This particularity made Dobereiner try to relate the chemical attributes of these elements with the atomic weights, appreciating a strong similarity between them and a gradual change from the first to the last, this ended up showing that the elements that can be observed in the periodic table, have a certain relationship between them, thanks to the analogy between their compounds and their properties.
As already mentioned, Dobereiner also observed how three elements, such as chlorine, bromine and iodine, were similar in their properties, with only a small change from the first to the last and he realized that the same happened with another group of elements, which is why these groups were given the name of triads and by the year 1850, at least 20 had already been discovered, which indicated a certain recurrence between the chemical elements.
The importance of these triads resides, in that it would be the first time, that all the elements with equivalent attributes were grouped, anticipating the concept of chemical families, which would come later.
