University Students’ Preferred Models of Chemical Bonding

This paper shows how students’ preferred model of covalent bonding, exemplified by the hydrogen molecule, changes during their first two years of university studies. It analyzes some differences between first-year, second-year, and third-year students and between students who prefer different models. Chemistry students are introduced to several models and theories about chemical bonding and expected to integrate these models into a scientifically appropriate understanding of the topic, use them in constructive ways, and choose the most suitable model for the problem at hand. Research shows that students struggle with this and that even advanced students of chemistry tend to use simple models of chemical bonding, despite having learned more sophisticated models. This study analyzes first-year (N = 321), second-year (N = 221) and third-year (N = 199) chemistry students’ responses to a survey about students’ perceptions of chemical bonding and models of chemical bonding. Most first-year students chose either an octet model or a Lewis structure as their preferred model, while other models, such as a molecular orbital diagram, were popular among second- and third-year students. The study found a link between students’ preferred model and how students explain chemical bonding: Students who preferred different models used different concepts when describing chemical bonding and justified their choice of preferred model differently.