4 nov 1827 - Dobereiner

Description:

He was a German scientist. He had his law called "triads law". Each of Dobereiner's triads was a group of three elements. The appearance and reactions of the elements in a triad were similar to each other. He discovered that the relative atomic mass of the middle element in each triad was close to the relative atomic masses of the other two. This gave the clue to other scientists that the arrangement by atomic mass matters.