From Simple Substance to Chemical Element

Abstract The introduction of the modern concept of chemical element has often been credited to Lavoisier. I will argue that despite the significant impact of the definition of elements as non-decompound bodies in Lavoisier’s “Elements of Chemistry,” this claim is misleading for at least three reasons. First, elements were already defined as residues of analysis prior to Lavoisier. Second, Lavoisier did not totally give up the traditional view of elements as constituents of all bodies. Third, the modern definition of chemical element implies a clear distinction between simple bodies and elements that was later introduced by Dmitri Mendeleev. I will outline the role of this conceptual distinction in Mendeleev’s process of classification of elements and symmetrically emphasize how the periodic system contributed to stabilize his notion of element as an individual defined by its position in the system. Thus the concept of element appears as both a precondition and a product of the construction of the periodic system.