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Empedocles (over 2000 years ago)
Greek Philosopher Empedocles stated "all things are made of either fire, water, earth or air" - held by harmony and discord -
Robert Boyle (1661)
"I now mean by elements...certain primitive and simple, or perfectly unmingled bodies; which not being made of any other bodies, or of one another, are the ingredients of which all those perfectly mixed bodies (chemical compounds) are immediately compounded, and into which they are ultimately resolved" - Elements are the basic building blocks of matter -
Dalton (1803)
All elements were composed of atoms that had identical properties and mass -
Dmitri Mendeleev (1869)
Gathered descriptions of properties of over 60 elements -
Dmitri Mendeleev (1870)
It was possible to predict the properties of undiscovered elements that can be made using the table -
Lothar Meyer (1870)
Developed a periodic table based on atomic masses, in which peaks were found in group 1
