Each element has a symbol listed on the periodic table of elements, which generally is an abbreviation of its name, (i.e. Al for Aluminum) but sometimes these symbols are derived from Latin words (i.e. Au for Gold.)
Chemical formulas for molecules composed of only one type of element can be either monatomic or diatomic. Monatomic molecules consist of a single atom. The only monatomic molecules are those formed by the noble gases (the elements in the last column of the periodic table, helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and radon (Rn).