Despite representations' central role in conveying chemical phenomena, mastering them is not trivial, given the wide variety of different conventions to interpret and use them. Furthermore, instructional approaches and materials may overlook explicit discussion on how students should reason with representations. To gather evidence that could guide improvements in teaching strategies and the creation of more effective instructional materials, we explored how students use Lewis structures to make inferences about stability. Through interviews with twenty-eight organic chemistry students, we have captured a range of resources that they employed, including the features of Lewis structures they paid attention to, the conceptual resources they activated, and the sophistication of their explanations. We found that students referenced all the explicit features of the provided Lewis structures but primarily attributed stability to the unique eye-catching features of each representation. Importantly, the surface features to which students attended impacted the conceptual resources they activated and their reasoning. Specifically, some students misapplied chemical principles to make justifications that fit their correct or incorrect claims about stability. Moreover, students primarily relied on lower-level reasoning and heuristics when constructing explanations. These findings underscore the importance of probing student reasoning so that instruction and assessments can be tailored to enhance students' ability to effectively use representations to reason about chemical phenomena. By understanding the reasoning patterns students adopt, educators can develop targeted strategies that promote deeper understanding and productive use of chemical representations.