Section 18.11 Draw an electron-dot structure for hydrogen peroxide. Write balanced chemical equations for reactions of hydrogen peroxide, and tell whether hydrogen peroxide is acting as an oxidizing agent or a reducing agent in the reactions. Section 18.12 Section 18.13 Section 18.14 Section 18.15 Use structure and bonding concepts to explain the physical and chemical properties of elemental oxygen and ozone. Explain hard water and how hard water can be softened by ion exchange.