Addresses AP® Chemistry Big Idea 2 and Learning Objective 2.22. Teach this using either the guided or inquiry activity. Guided activity: students classify 12 solids as ionic solids, covalent network solids, molecular solids, or metallic solids based on properties they test. Inquiry activity: students test the properties of 4 solids, develop their own set of characteristics to distinguish between each bonding type, then apply their rules to classify 8 more solids. For 30 students in teams of 3.