Nomenclature of Elements with Atomic Numbers > 100

The Need for a Systematic Naming System

For most of chemistry's history, the discoverer of a new element had the privilege of naming it, subject to ratification by the International Union of Pure and Applied Chemistry (IUPAC). This tradition worked well for elements discovered in the 18th and 19th centuries, but it ran into serious trouble with the synthetic, superheavy elements of the 20th century.

The problem is that elements with atomic numbers above 100 are extraordinarily unstable. They exist only for fractions of a second, and are produced in quantities of just a few atoms at a time — sometimes only a single atom. Synthesising and characterising them requires immensely sophisticated and expensive equipment, and the work is carried out in only a handful of laboratories worldwide, often in fierce competition.

This competitive atmosphere led to disputes. For example, both American and Soviet scientists claimed credit for discovering element 104. The Americans proposed the name Rutherfordium (after Ernest Rutherford), while the Soviets proposed Kurchatovium (after Igor Kurchatov). Neither side would yield, and the element went by two names for years.

To prevent such controversies from recurring, IUPAC established a systematic nomenclature that can be applied to any element, regardless of who discovered it. This system gives every new element a temporary, unambiguous name and symbol derived directly from its atomic number — no personal or national bias involved. Only after the discovery is fully confirmed and officially recognised does the element receive its permanent name.

The IUPAC Numerical Roots

The systematic name is built from a set of numerical roots for the digits 0 through 9. These roots are listed in the table below.

How to Construct the Systematic Name and Symbol

The procedure is straightforward:

1. Write down the atomic number $Z$ of the element.
2. Take the digits of $Z$ in order, from left to right.
3. For each digit, write the corresponding root from the table above.
4. Concatenate these roots to form a single word.
5. Add the suffix -ium to the end of the word.
6. The temporary symbol is formed by taking the first letter of each root's abbreviation, in the same order, and writing them as a three-letter symbol.

Problem 3.1 in this section's Problems group below applies these rules to the element with atomic number $Z = 120$.

The IUPAC Names for Elements with $Z > 100$

The table below shows the systematic names and symbols for all elements with atomic numbers from 101 to 118, alongside their now-official permanent names and symbols. This table is the complete set from the textbook.

From Temporary to Permanent …