L’ensenyament del concepte element químic i de la taula periòdica a l’educació secundària

catalaEls conceptes substancia elemental, compost, element quimic i llei periodica constitueixen termes fonamentals del curriculum de quimica de l’educacio secundaria. En el present article, abordem el significat d’aquests conceptes, fem algunes consideracions sobre la seva evolucio historica, considerem els enfocaments mes habituals per al seu ensenyament, fem una revisio bibliografica sobre la investigacio i les propostes didactiques que s’han fet en les ultimes decades i, finalment, proposem un proces modelitzador de les nocions substancia elemental, element i taula periodica que en te en compte l’evolucio historica i els diferents nivells de conceptualitzacio.paraules clau: Element quimic, substancia elemental, llei periodica, taula periodica, propietats periodiques. EnglishThe concepts elemental substance, compound, chemical element and periodic law constitute fundamental concepts of the chemistry curriculum of secondary education. In this article, we approach the meaning of these concepts, we make some considerations about their historical evolution, we consider the most common approaches to their teaching, we do a bibliographic review on the research and the didactic proposals that have been made in the last decades and, lastly, we propose a modeling process of the concepts elemental substance, element and periodic table which takes into account its historical evolution and the different levels of conceptualization.keywords: Chemical element, elemental substance, periodic law, periodic table, periodic properties.