mar 2, 1860 - De Chancourtois was a French scientist and the first to arrange the periodic table considering the atomic weight of elements. This way, he made use of a physical property that can be represented as numbers. The elements were arranged in order of increasing weight. He arranged the elements in a cylinder as a spiral called telluric helix. The helix allowed to see similar elements lined up vertically
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Date:
mar 2, 1860
Now
~ 166 years ago