Diagnosing and Promoting the Understanding of Chemical Bonding Theory

Researcher Adrian Zwyssig

Overgeneralization is a major challenge in science education. A prominent example in the field of chemistry education is the understanding of the core topic of chemical bonding theory. Typically, students neglect the differences between the three kinds of chemical bonds, i.e. covalent, ionic and metallic bonds, and mistakenly apply the model of covalent bonding to both metallic as well as ionic compounds. This was confirmed by our assessment of first year students’ knowledge about bonding theory before attending lectures at the ETH Zürich (September 2020, N = 1030). The study revealed the prevalence of various misconceptions like, for example, the overgeneralization of the model of covalent bonding, as well as uncertainties concerning the differences between chemical bonds and intermolecular forces. Thus, the question arises, how can we promote a better understanding of chemical bonding theory?
Comparing and contrasting activities have been proven effective for learners to keep the differences between similar concepts in mind. Therefore, I designed teaching materials containing many comparing and contrasting activities to highlight the differences between the three kinds of chemical bonds. In an ongoing pre- and post-test classroom intervention study at various Swiss gymnasiums (N = approx. 260), an experimental and a control group are investigated. With the experimental group (comparing and contrasting), we investigate the effectiveness of our newly developed teaching materials. Additionally, a control group using best practice instruction is examined to obtain a realistic assessment of the learning gains in regular chemistry lessons. Preliminary results from the pilot study are promising. Accordingly, we have strong evidence that the materials used in the intervention group are much better suited to promote conceptual change about chemical bonding theory than the best practice materials.