What are the letters that represent a chemical element called?

The term that refers to the letters used to represent a chemical element is known as the Atomic Symbol. Each chemical element is assigned a unique symbol, typically consisting of one or two letters derived from its name, often taken from Latin or Greek. For example, the symbol for hydrogen is 'H', while the symbol for carbon is 'C'. These symbols are used universally in the field of chemistry to allow for quick and clear communication about elements, regardless of language differences.

The other terms do not accurately describe this concept. Atomic Mass refers to the mass of an atom, usually expressed in atomic mass units, which is not the same as a symbol. Atomic Structure describes the arrangement of protons, neutrons, and electrons within an atom, and does not pertain to the letters representing elements. Molecular Formula defines the number and types of atoms in a molecule, rather than the elemental symbols themselves. Thus, Atomic Symbol is the correct choice as it directly pertains to the letters that represent elements.