Written for the middle school reader, this engaging and accessible book explores the useful compounds made with chlorine (table salt, for example), and how it is used as a bleaching agent, in food preparation, and in water purification. Readers may be surprised to discover that chlorine is a necessary component of PVC (polyvinyl chloride), one of the most versatile forms of plastic used in construction today. Full-color photos of lab experiments illustrate the unique properties of potassium, and diagrams and illustrations of atomic structures elucidate the text.