Gold is considered an element because it is a chemical substance made up of only one type of atom, with the atomic number 79 and the symbol Au (from the Latin word aurum). As an element, gold cannot be broken down into simpler substances by ordinary chemical means. It is a transition metal with unique properties such as luster, softness, and high resistance to corrosion and tarnish, which show that it is a pure substance with a definite chemical composition.