Henry Cavendish discovered hydrogen as a colorless odorless gas
In 1789, Antoine Lavoisier grouped the elements based on their properties into gases, non-metals, metals and earths.
In 1829, Johann Döbereiner recognized triads of elements with similar properties he showed that the properties of the middle element could be predicted from the properties of the other two.
John Newland arranged the elements in order of atomic weights and observed similarities between some elements
Dmitri Mendeleev made a periodic table that was arranged by the atomic mass and arranged periodically with elements similar with similar properties under each other
