Which Letters Are Missing from the Periodic Table?

The periodic table organizes all known chemical elements by atomic number, electron configuration, and recurring chemical properties. Each element has a unique one- or two-letter symbol derived from its English, Latin, or other historical name. Surprisingly, not all 26 letters of the English alphabet appear in these symbols. This article delves into the absent letters, their historical context, IUPAC naming conventions, and why certain characters remain unused in official nomenclature.

Overview of Element Symbol Composition

Element symbols follow strict rules set by the International Union of Pure and Applied Chemistry (IUPAC). The first letter is always capitalized, and the second (if present) is lowercase. Symbols often derive from English names (e.g., H for hydrogen), Latin (e.g., Fe for iron, from ferrum), or discoverers’ preferred terms. As of 2026, the periodic table includes 118 confirmed elements, from hydrogen (atomic number 1) to oganesson (118). Despite this diversity, two letters stand out for their complete absence: **J** and **Q**.

These omissions are not random. They stem from linguistic patterns in element names, historical naming practices, and systematic rules for undiscovered elements. Understanding this requires examining each missing letter individually, alongside the broader framework of chemical nomenclature.

The Curious Case of the Letter J

The letter **J** is entirely absent from both element symbols and official English names on the current IUPAC periodic table. No element uses J as its initial or secondary letter. This has been true since the table’s modern standardization.

Historically, J appeared in early versions. In Dmitri Mendeleev’s original 1869 periodic table, the symbol “Jod” (or J) represented iodine, derived from the French iode. At the time, iodine’s symbol was debated, with some chemists favoring J over the now-standard I. Mendeleev’s table reflected regional naming variations, particularly in Germanic languages where “J” pronounced like “Y” was common for iodine.

By the early 20th century, IUPAC standardized symbols globally. Iodine retained “I,” eliminating J. No new elements have since incorporated J, partly because discoverers avoid it, and no natural or synthetic element name naturally includes it. For instance, elements like jojoba (a plant, not an element) or jargon are irrelevant to chemistry.

In Latin-based names, J is rare, as classical Latin lacked a distinct J (using I or consonantal I). Modern English element names, drawn from mythology, places, or scientists (e.g., einsteinium, Es), bypass J due to phonetic and orthographic preferences.

Why Q Remains Unrepresented

The letter **Q** fares similarly to J, appearing nowhere in official element symbols or names. Unlike J, Q has never been used in any historical symbol on recognized tables. Its absence is tied to English phonetics and naming conventions.

English words starting with Q typically require a following U (e.g., quantum, quartz). No element name follows this pattern permanently. Temporary placeholders are an exception, discussed later. Official names like oxygen, gold, or seaborgium avoid Q entirely.

Linguistically, Q is uncommon in scientific Latin or Greek roots, which dominate element etymology. For example, “quad” (four) appears in temporary names, but final names like nihonium (113) replace such stems with culturally significant terms.

Temporary Naming System and Placeholder Letters

IUPAC provides systematic names for newly discovered superheavy elements until permanent names are approved. These use numerical roots based on atomic number, combined with Latin prefixes and the suffix “-ium.”

The root system is:

For element 114, the temporary name was ununquadrium (Uuq), incorporating “q” from quad. It was later named flerovium (Fl). Element 116 was ununoctium (Uuo), now tennessine (Ts). These placeholders introduce Q when the atomic number includes 4, but final names eliminate it.

Future superheavy elements (e.g., 124: unbiquadium, Ubq) will temporarily feature Q, but likely drop it upon naming.

Historical Periodic Tables and Evolving Symbols

Early periodic tables varied in symbols. Mendeleev’s included J for iodine and other non-standard notations. The 1923 IUPAC table solidified current symbols, excluding J and Q.

Some educational charts retain outdated symbols for historical illustration. Modern official tables, like those from IUPAC or the American Chemical Society, confirm the absences.

Full Inventory: Letters Present in Symbols

To appreciate the omissions, consider represented letters. All except J and Q appear at least once:

• A: Aluminum (Al)
• B: Boron (B)
• C: Carbon (C)
• D: Deuterium (D, isotope notation)
• E: Einsteinium (Es)
• F: Fluorine (F)
• G: Gadolinium (Gd)
• H: Hydrogen (H)
• I: Iodine (I)
• K: Potassium (K, from kalium)
• L: Lanthanum (La)
• M: Magnesium (Mg)
• N: Nitrogen (N)
• O: Oxygen (O)
• P: Phosphorus (P)
• R: Radium (Ra)
• S: Sulfur (S)
• T: Titanium (Ti)
• U: Uranium (U)
• V: Vanadium (V)
• W: Tungsten (W, from wolfram)
• X: Xenon (Xe)
• Y: Yttrium (Y)
• Z: Zinc (Zn)

This list confirms J and Q’s uniqueness. Note: D is primarily isotopic, but symbols like Ds (Darmstadtium) reinforce it.

Implications for Chemistry Education and Trivia

This factoid engages students, highlighting nomenclature’s quirks. It underscores IUPAC’s role in standardizing science amid linguistic diversity. In trivia, it’s a staple: “Name the letters missing from the periodic table.”

For researchers, it reflects naming evolution. Discoverers propose names honoring scientists, places, or properties, inevitably avoiding J and Q.

Future Prospects: Will J or Q Ever Appear?

Superheavy elements beyond 118 may introduce new symbols, but trends suggest continued absence. Discoverers prioritize meaningful, pronounceable names without rare letters. Unless a scientist named “Jaxon” or place “Quartzium” is honored, omissions persist.

Extended tables for hypothetical elements use the same temporary system, perpetuating Q temporarily but not permanently.

Frequently Asked Questions (FAQs)

What letters are missing from the periodic table?

J and Q do not appear in any official element symbols or names.

Was J ever used in an element symbol?

Yes, in Mendeleev’s table for iodine (Jod), but not in modern IUPAC versions.

Does Q appear in temporary element names?

Yes, in placeholders like ununquadium (Uuq) for element 114, before naming as flerovium.

Why avoid J and Q in element names?

Linguistic rarity in scientific roots and historical standardization exclude them.

How many elements are on the periodic table today?

118 confirmed elements as of 2026.

Written by

Sneha Tete

• Integrated M.A. in Applied Linguistics, University of Hyderabad
• 5+ years in editorial, instructional, SEO, and research-based writing

Sneha is a relationships and lifestyle writer with a strong foundation in applied linguistics and certified training in relationship coaching. She brings over five years of writing experience to theskillvault,  crafting thoughtful, research-driven content that empowers readers to build healthier relationships, boost emotional well-being, and embrace holistic living. Her writing and insights reflect the belief that beauty, happiness, and wellness…