Chemistry Learners’ Preferred Mental Models for Chemical Bonding

Abstract

Preferred mental models of 30 learners from three educational levels, senior secondary, undergraduate, and graduate (master of science and PhD) were probed using a three-step interview
protocol. In the first step the participants were shown common substances such as table salt and asked to explain the bonding. Next they were shown events depicting physical or chemical properties (for example malleability and conductivity) and asked to use their mental models to explain the event. Finally, they were shown depictions of mental models drawn from curriculum material and asked for their preference. Data also were collected from curriculum material and interviews of faculty. These latter data resulted in the identification of three target systems for chemical bonding (namely, metallic, ionic, and covalent), and eight target models (molecular orbital theory, sea-of-electrons, etc.) which were negotiated and became socially-situated consensus teaching models, used to interpret interview data. The findings suggest learners across all academic levels prefer simple, realistic-looking mental models, and varied to the extent to which they were able to use them to explain common physical and chemical properties of substances.