This article aims to investigate how science teachers engaged with the macroscopic, sub-microscopic and symbolic levels of representations in their Chemistry teaching. Data were collected in Limpopo province in South Africa from 15 "lead" teachers and this paper reports on five lessons presented by the teachers during professional development workshops. The "lead" teachers were selected by the Department of Education based on their qualifications, years of experience and results of their learners over the years. Data were gathered from video-recorded peer teaching lessons, field notes and post-lesson interviews. The findings show that the teachers in this study mainly focused on the symbolic and sub-microscopic level and did not engage with the content at all three levels, even though they participated in a professional development programme specifically geared towards the integration of all three levels. These findings, although they cannot be generalised because of the small sample size, indicate a need for changes in the pre-service and in-service teachers' training, and in the curriculum in South Africa. The challenge facing the teaching of Chemistry in South Africa is to evolve suitable didactic practices to preserve the unity of Chemistry at all three levels of representation.