Abstract
The thematic unit Chemical Reactions was identified as a critical point and also as a key point in the chemistry curriculum in lower secondary school, based on interviews with teachers of chemistry under an OP RDE research project called "Didactics: Man and Nature A". The lowest average success of pupils in this topic in the Czech Republic and abroad is also evident from the results of the TIMSS 2007.
Therefore, in this paper, we have dealt with the circumstances of this situation and its possible improvement, in a broader context. We present a study of legislative documents (the Framework Education Program for Basic Education, etc.), as well as the thematic unit in Czech chemistry textbooks for lower secondary schools, and follow with proposals for an array of experiments, experimental cycles, etc., focused on the reactivity of chemicals.
The array of experiments are experimental cycles relating to copper and its compounds, which are characterized by significant color changes or changes in the state of matter of the compounds of the reaction mixture. This can be instrumental in the more precise classification of chemical reactions according to selected criteria by learners and their better understanding of chemical reactions through analyzing the course of these experiments, supplemented by simple tests for determining reaction products.