3.1 States of Matter3.2 Why Atoms Aggregate to Form Solids Beyond Form Simple Bonds3.3 Aggregation with Metallic Bonding: Metal Crystal Structures3.4 Aggregation with Ionic Bonding: Ceramic Crystal Structures3.5 Aggregation with Covalent Bonding: Crystalline Carbon, High-Performance Ceramics, Metalloid Semiconductors, Silicates, and Polymer Macromolecules3.6 Aggregation of Macromolecules by Secondary Bonding to Form Polymers3.7 A System for Navigating Within Crystals: Miller Indices3.8 Noncrystalline Materials: Why and When They Occur3.9 Characterizing Crystalline StructuresSummaryThinking Problems and Exploration Questions