The purpose of this study was to explore the relationship between teachers' (N = 69) participation in constructivist chemistry professional development (PD) and enhancement of content (CK) and pedagogical content knowledge (PCK) (representational thinking and conceptual change strategies) and self-efficacy (PSTE). Quantitative measures assessed CK, PCK, and PSTE. Document analysis focused on PCK. Elementary teachers gained CK, PCK, PSTE, and designed lessons to advance thinking from macroscopic to abstract models. Middle/secondary teachers gained PSTE, PCK, and introduced macroscopic models to develop understanding of previously taught abstract models. All implemented representational thinking and conceptual change strategies. Results suggest that: (1) constructivist PD meets the needs of teachers of varying CK, and (2) instruction should connect representational models with alternative conceptions, integrating radical and social constructivism.