Carbon is considered tetravalent because it has four electrons available to form chemical bonds with other elements. These electrons are called valence electrons and are located in the outermost electron shell.
Carbon is one of several tetravalent elements. The other elements are germanium, tin, silicon and lead. Together, the tetravalent elements form group 14 of the periodic table, which is the group of elements located in the 14th column. Unlike the other tetravalent elements, carbon is found in large quantities in living things. Carbon also has the ability to form more complex molecules than the other tetravalent elements due to its ability to form both double and triple bonds. Common carbon molecules include carbon dioxide (CO2), methane (CH4) and acetylene (C2H2).
Carbon is considered essential to the formation of many biological molecules. Its tetravalent nature gives it the ability to form DNA, carbohydrates and proteins that are necessary for many biological processes. The study of carbon compounds is known as organic chemistry.
Carbon's symbol is C, and its atomic number is 6. Its atomic weight is 12.011. The name carbon comes form the Latin "carbo," meaning charcoal. At room temperature, carbon exists as a black solid. Carbon's existence has been known since antiquity.