To gauge the resources activated by each problem, students were not given specific prompts directing them to a certain model (i.e., "draw a resonance structure"). The resonance structures needed to answer each item are summarized in Box 2. Students were allowed to apply the resources they felt were most appropriate for solving the problems. For problem A, 185 drawing a nonequivalent resonance structure with nonzero formal charges on the nitrogen atoms allows for the correct conclusion. The nitrogen with a negative formal charge has increased electron density and is more basic.