5 jan 1869 ano - Dmitri Mendeleev arranged elements into 7 groups.

Descrição:

Dmitri Mendeleev was a chemist that pursued studying atoms for much of his career. Mendeleev used the North American game solitaire to build what we know as the periodic table. Mendeleev arranged element cards to create the periodic table. In 1869, Mendeleev arranged elements into 7 groups with similar properties and components. He discovered that the properties were also the atomic weight. All of this became known as the Periodic Law.