Student learning in the classroom depends pre-eminently on the knowledge an instructor draws from when teaching a particular subject area to a particular group of students, also known as pedagogical content knowledge. While studies over the last decade have shed some light on the general pedagogical knowledge of science, technology, engineering and mathematics (STEM) instructors and their implementation of that knowledge in the classroom, the pedagogical content knowledge (PCK) of a STEM faculty is a largely overlooked area of inquiry. However, its investigation is critical in this era of instructional reforms, as studies have shown that PCK is essential for the effective implementation of active learning strategies. In this study, we conducted semi-structured interviews to probe the enacted pedagogical content knowledge (ePCK) of seven post-secondary organic chemistry instructors on the topic of resonance. Additionally, we administered an open-ended survey on resonance to students enrolled in these instructors' courses, to gauge their conceptual understanding. From the interviews, the instructors were assigned to one of four groups based on their ePCK of the resonance hybrid. Our findings do not conclusively support the notion that students develop a better conceptual understanding from instructors who hold a more comprehensive and integrated ePCK.