Questions were modified to ensure that each question included a representation of bonding, and for questions that were quite similar to one another, one of the “duplicates” was eliminated. The final version of the BRI consisted of 23 multiple-choicequestions (7 one-tier and 8 two-tier questions) in a paper-and-pencil format, all of which included at least one bonding representation and all of which focused on one of the four themes identified through analysis of the student interviews conducted to better understand how studentsdistinguish between ionic and covalent bonding