Assessing the Quality of Models Upper-division Chemistry Students Develop and Apply in the Context of the Hydrogen Atom

Quantum chemistry provides us with useful models to predict and explain atomic and molecular scale phenomena. Thus, a reasonably well-developed understanding of this domain is essential for undergraduate students of chemistry. Students’ abilities to develop, apply, and build upon scientific models in quantum chemistry, particularly in upper-division settings, have not been well studied in chemistry education research. We report the findings from think-aloud interviews administered to upper-division students in quantum chemistry courses at both a large, public regional comprehensive university and a small, private liberal arts college. The interviews centered on a task designed to allow students to develop, apply, and extend a model of the atom. Interview transcripts and sketches were coded using software for qualitative data analysis, and we applied literature-grounded coding schemes to systematically describe the level of models students were able to develop and apply for the atom, as well as the nature of students’ fragmented understanding of such models. Our preliminary findings indicate 1). many students exhibit fragmented understanding of model components that are necessary for effective meaning-making, 2). students experience difficulty with appropriate mathematization of their models—even with access to all relevant expressions for the quantum mechanical model of the atom. Implications for future work and instructional practice are also discussed