The dual conception of the chemical element: epistemic aspects and implications for chemical education

In the present work, the notion of chemical element is analyzed from the perspective of chemical education. Chemists refer to elements either as the final term of chemical analysis (i.e., simple substances) or as what persists in a chemical change. This duality has deep historical roots and it is sanctioned by IUPAC’s definition of chemical element. Nevertheless, it is inherently contradictory and it may result in deep misunderstandings in the educational context. After discussing the problems raised by the identification of the element with any material body—either macroscopic or microscopic—we analyze a number of definitions of elements, proposed by chemists, epistemologists, and educators. After pointing out the strengths and weaknesses of such definitions, we argue that the chemical element is a unifying chemical concept that designates an abstract category, identified by the atomic number.