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On 17 February 1869, Russian chemist Dmitri Mendeleev jotted down the symbols for the chemical elements, putting them in order according to their atomic weights and inventing the periodic table.

The modern periodic table, arranged in rows and columns, was first introduced by Dmitri Mendeleev in 1869. At the time, it included the known elements and their properties, but Mendeleev predicted ...

MORE - UEFA Champions League hub — Format, schedule, more The schedule was longer, the table bigger, and we’ve now seen how chaotic a final matchday can look, with all 18 games played at the same time ...