may 26, 1820 - Discovery of the Relative Atomic Mass (Dobereiner)
Description:
He discovered how the relative atomic mass of the middle element in a group of three is almost halfway between the lightest and the heaviest ones in the group. He called these pattern a “triad”. He organized many of the elements that (at that time) were discovered that way.Added to timeline:
Date:
may 26, 1820
Now
~ 206 years ago