Lithium is an element<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref>in the Alkali metals class of the periodic table. It is the lightest solid element--about half the density of water. | Lithium is an element<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref>in the Alkali metals class of the periodic table. It is the lightest solid element--about half the density of water. |