Encyclopedia of Science | Alkali Metals

• Lithium
• Sodium
• Potassium
• Rubidium, cesium, and francium

The alkali metals are the elements that make up Group 1 of the periodic table: lithium, sodium, potassium, rubidium, cesium, and francium. These elements are all much too active to exist in nature in their native state. However, they do form a number of important compounds, such as table salt (sodium chloride), borax (sodium tetraborate), potash (potassium carbonate), and washing soda (sodium carbonate).

Because the alkali metals all have one electron in the outer orbit of their atoms, they have similar chemical and physical properties. All are shiny, soft enough to cut with a knife, and—with the exception of cesium—white. They all react with water vigorously to form hydrogen gas and the hydroxide of the metal. As an...