An (blank) is an abbreviation for the name of an element and usualy has eighter one or two letters

Atomic symbol

The atom of each element is made up of electrons, protons and neutrons. All atoms of the same neutral element have the same number of protons and electrons but the number of neutrons can differ. Atoms of the same element but different neutrons are called isotopes. Because of these isotopes it becomes necessary to develop a notation to distinguish one isotope from another - the atomic symbol

The Chemical Symbol is the Abbreviation for the name of an element.