Mastering the ability to construct and manipulate Lewis structures is an important first step along the journey to reaching representational competence. Lewis structures serve as a convenient organizational scheme that can help students to scaffold their chemical knowledge and help them to apply it to predict a variety of physical and chemical properties. Our previous research documented the many problems that students encountered in developing these skills and suggested that cognitive load may play an important role in the successful construction of Lewis structures. This study sought to better understand the structural characteristics and complexities that contributed significantly to the cognitive load of chemistry students drawing Lewis structures and to determine how those load-inducing characteristics changed as students gained additional chemical expertise. The results of the inquiry show that the inclusion of nearly any structural characteristic induced a significant increase in cognitive load for novice chemistry students, but these trends are mitigated as students gain additional chemical expertise.