CLASSIFICATION OF CHEMICAL SUBSTANCES: A LITTLE-EXPLORED CONCEPT IN CHEMICAL EDUCATION

The classification of chemical substances is a concept little explored in Chemistry teaching literature and in Chemistry textbooks at higher and secondary levels. The aim of this paper is to discuss theoretically the importance and contributions of this concept for teaching and learning Chemistry. The History of Chemistry reveals that the chemical criteria for classifying materials came up with the modern concepts of chemical element and chemical reaction, which gave rise to the notion of chemical similarity. Later, such similarity was related to molecular structure through functional groups. The classes of substances are related throughout chemical reactions, during which substances of given classes are transformed into substances of other classes, constituting a wide network. The classification of chemical substances can contribute to the intellectual development of Chemistry students, in order to study it, it becomes necessary to understand its theoretical foundation, as well as its characteristics of objectivity, completeness, simplicity and prediction. In this sense, one can contribute to the stimulation of perception, attention and abstraction that are typical of the chemical ways of thinking and communicating necessary for learning the chemical concepts linked to classification.

化学物质分类在高等及中等教育阶段的化学教学文献与化学教材中，均属于较少被深入探究的议题。本文旨在从理论层面探讨该概念对于化学教与学的重要意义与应用价值。化学史研究显示，物质分类的化学判据随化学元素与化学反应的现代概念应运而生，由此催生了化学相似性的核心认知。后续，这类相似性通过官能团与分子结构建立起了系统性关联。各类化学物质可通过化学反应实现跨类转化，即特定类别的物质可转变为其他类别的物质，进而构成了一张覆盖广泛的分类网络。化学物质分类有助于促进化学学习者的智力发展；而为了开展该主题的学习，学习者需明晰其理论根基，以及客观性、完备性、简洁性与可预测性等核心特征。据此，该主题可有效助力培养感知能力、专注力与抽象思维——这些均是掌握与分类相关的化学概念所必需的典型化学思维模式与表达范式。