Element symbols are the universal abbreviations used to represent the 118 confirmed chemical elements. This standardized system allows scientists across the globe to communicate clearly about chemical reactions and compositions. Each element is assigned a unique symbol, typically one or two letters, which serves as a concise identifier. Not every letter in the English alphabet is used, particularly as the starting character for an element.
The Missing First Letters: J and Q
The letters J and Q are the only two letters in the English alphabet that do not appear as the initial character of any element symbol. This absence is primarily a result of the historical linguistic sources used for naming elements, which relied heavily on Latin, Greek, and other languages where these letters were rare or did not exist in their modern form. The letter ‘J’ was a relatively late addition to many languages, often being used interchangeably with ‘I’ in Latin-derived words for centuries.
The element Iodine, for instance, was known as Jod in several languages and was symbolized with ‘J’ on early periodic tables, such as Dmitri Mendeleev’s 1871 chart. However, the current symbol is the single letter ‘I,’ determined by international convention. The letter ‘Q’ is also uncommon in the historical names used for element discovery.
Even though ‘Q’ does appear in the temporary systematic names for undiscovered or recently confirmed elements, it is never the first letter of the official, permanent symbol. Element 114, for instance, was temporarily named Ununquadium (Uuq), but its final symbol is Fl for Flerovium.
How Element Symbols Are Named and Standardized
The International Union of Pure and Applied Chemistry (IUPAC) is the global authority responsible for confirming the discovery of new elements and officially assigning their names and symbols. Official symbols consist of either one or two letters. The first letter must always be capitalized, and the second letter, if present, must be in lowercase, such as H for Hydrogen or Ca for Calcium.
Element symbols are most often derived from the element’s modern English name, but they can also originate from historical or Latin names. For example, the symbol for Sodium is Na, which comes from its Latin name Natrium, and Gold is Au, from Aurum. This practice of using older names is necessary because many elements share the same first letter, requiring a second, distinguishing letter.
For new elements that have been discovered but not yet officially named, IUPAC assigns a temporary, three-letter systematic symbol based on the atomic number. This nomenclature uses Greek and Latin roots to represent the digits of the atomic number, such as Ununennium (Uue) for element 119. Once the element’s discovery is verified and a permanent name is chosen, the three-letter symbol is replaced with the final one- or two-letter designation.