The previously published Anchoring Concepts Content Map (ACCM) from the ACS Examinations Institute is updated. Through the development process of the ACCM for other subdisciplines, changes have been made at the top two levels, and these changes need to be reflected in the previously published maps. In addition, a large-scale project to align test items from ACS Exams over the past 20 years revealed specific omissions in the initially published General Chemistry ACCM.

Teachers use multiple representations to communicate the concepts of bonding, including Lewis structures, formulas, space-filling models, and 3D manipulatives. As students learn to interpret these multiple representations, they may develop misconceptions that can create problems in further learning of chemistry. Interviews were conducted with 28 high school physical science, high school chemistry, and general chemistry students. The interviews focused on identifying student understanding of, and misconceptions about, covalent and ionic bonding representations through analysis of both student-created and expert-generated representations. Misconceptions about bonding representations were identified regarding four themes: (i) periodic trends, (ii) electrostatic interactions, (iii) the octet rule, and (iv) surface features. The Bonding Representations Inventory (BRI) was developed to quantify the prevalence of these misconceptions. The BRI was administered to 1072 high school chemistry, advanced placement chemistry, and general chemistry students across the United States. Content validity was determined through expert validation of the items, and concurrent validity was established by comparing the three groups of students. Reliability was determined through individual item analysis and through Ferguson's δ. Suggestions are offered for using the BRI in high school and general chemistry classrooms to inform the teaching of both bonding and representations.

Introductory chemistry has long been considered a service course by various departments that entrust chemistry departments with teaching their students. As a result, most introductory courses include a majority of students who are not chemistry majors, and many are health and science related majors who are required to take chemistry. To identify content areas that are either well covered or sparsely covered, approximately 2000 exam items from four types of General Chemistry ACS exams (Full Year General Chemistry, General Chemistry Conceptual, First Term General Chemistry, and Second Term General Chemistry) spanning two decades were aligned to the Anchoring Concepts Content Map (ACCM). ACS exams were chosen as artifacts due to the nature of the exam development by committees consisting of chemists who are experts in the field. The ACCM is developed such that the statements from the first two levels are stable across the entire undergraduate chemistry curriculum, while the third and fourth levels are subdiscipline specific. It was found that there are 17 statements at the second level (Enduring Understanding) that have rarely been assessed on General Chemistry ACS exams over the past 20 years. Some of these topics appear in areas that are likely important for students whose interest lies in the life sciences, including no items testing the concept of intermolecular forces in the context of large molecules. These results suggest that chemistry curriculum reform efforts may benefit from considering specifics of content domain coverage.

As a discipline, chemistry enjoys a unique position. While many academic areas prepared "cooperative examinations" in the 1930s, only chemistry maintained the activity within what has become the ACS Examinations Institute. As a result, the long-term existence of community-built, norm-referenced, standardized exams provides a historical artifact about the nature of content coverage in courses that stretches over decades. This work reports efforts to capture information and formulate it into a database about general chemistry content coverage over the past 20 years. Roughly 2000 items have been characterized in several ways, including (i) content, using an Anchoring Concepts Content Map; (ii) item construct, such as the presence of symbolic or visual information; and (iii) cognitive processing required, in terms of recall, algorithmic, or conceptual thinking.

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