To learn meaningfully and to classify in chemistry

Abstract

In our context, the teaching of chemistry does not make enough emphasis on the chemical criteria of substances classification and the chances that these they for a meaningful learning of several kind of substances based on functional groups and on the differentiation between pure substances and homogeneous mixtures as well as and among other chemical and physical modifications. This teaching situation implies a devaluation of the relevance that meaningful comprehension has on chemical language. In general, the later comprise the formulation of substances and the formulated representation of chemical transformations. These formulated representations are a bridge between the world of substances, their chemical transformations and their conceptualization. The periodic system of chemical elements as a basic classificatory system for substances according to their elemental composition is a conceptual tool for meaningful teaching and learning of substance groups in relation with their common functional groups. This leads to the development of substances classificatory systems, which allow the students to interact with the diversity of substances, to work with previous knowledge and concepts formation processes and to make explicit their knowledge through natural language and the way they use and signify the language of relative and molecular chemical formulas.