Chemistry teachers share a vast array of multimodal representations with their students, who must possess a degree of representational competence to be able to recognise, interpret, construct, transform and connect between these representations. Learning is made possible through noticing or discerning something in a representation and reasoning about it in a meaningful way. In this study, the distribution and combination of representations that were adopted in a lecture resource (PowerPoint slides), used in a single-semester first-year chemistry course, were analysed (Ferreira J.E.V., Lawrie G.A. Chem. Educ. Res. Prac. 2019, 20(4), 902–23, http://doi.org/10.1039/c9rp00001adoi.org/10.1039/c9rp00001a). Hierarchical cluster analysis was applied to identify patterns and connectivity between representations while also aiming to identify any critical combinations of specific representations that may exist. It was found that students had been presented with at least 3367 separate representations in lectures during a single semester. Symbolic representations were the most prevalent form adopted by lecturers and there was very limited use of macroscopic representations in lectures. Five topic clusters were identified through statistical analysis – the highest number of representations that had potential to combine to support construction of understanding were observed in the cluster addressing concepts including spontaneity and redox. The outcomes of this study inform instructional design that supports development of students’ representational competencies.