Aristotle proposes the four element theory: earth, air, fire and water.
Wrote the first extensive list of elements containing 33 elements and distinguished between metals and non-metals
Proposed "Dalton's Law" describing the relationship between the components in a mixture of gases.
Developed groups of 3 elements with similar properties.
Arranged the known elements in order of atomic weights and observed similarities between some elements.
Produced a table based on atomic weights but arranged "periodically" with elements with similar properties under each other. His Periodic Table included the 66 known elements organised by atomic weights.
Determined the atomic number of each of the elements and modified the "Periodic Law"
Synthesised transuranic elements (the elements after uranium in the eriodic table)