A chemical symbol is an abbreviation of the name of a chemical element. The name is derived from the name of the element, which is usually in Latin. Chemical symbols are made up of one or two letters.
Only the first letter is capitalized; the second, if there is one, is lowercase. For example, the chemical symbol for helium is “He,” and phosphorous is “P.” Some elements have symbols derived from their English name; however, other elements have symbols derived from Latin. Examples of Latin-derived symbols include potassium “K” from kalium; silver “Ag” from argentum; and sodium “Na” from natrium.
New elements are often assigned temporary symbols that consist of three letters. For example, the temporary name given to the element hassium was “Uno,” which was temporarily named "unniloctium."