Naming chemical elements often reflects significant scientific or cultural events, linking new elements to celestial bodies. The custom frequently draws upon the names of planets, dwarf planets, and their mythological counterparts. This nomenclature establishes a connection between the cosmos and the building blocks of matter, often creating sequential patterns on the periodic table.
Elements Named After the Outer Planets
The most sequential examples of celestial nomenclature involve elements named after the three outermost planets known at the time of their discovery. This tradition began with Uranium (U), which German chemist Martin Heinrich Klaproth named in 1789 to honor the planet Uranus, discovered by William Herschel just eight years earlier in 1781.
The pattern continued nearly 150 years later with the first synthetic elements (atomic numbers greater than 92). Element 93, Neptunium (Np), was discovered in 1940 by Edwin McMillan and Philip Abelson. They named it after Neptune, the next major planet beyond Uranus, intentionally linking the element’s increasing atomic number to the planet’s increasing distance from the Sun.
Following this logic, Glenn Seaborg and his team isolated element 94 in 1941, naming it Plutonium (Pu) after Pluto, which was then considered the next planet beyond Neptune. Although Pluto was reclassified as a dwarf planet in 2006, the element’s name preserves its status at the time of its discovery.
Elements Named After Earth and the Moon
The practice of using celestial names also extends to Earth and the Moon, drawing on classical mythology. The element Tellurium (Te) was named in 1798 by Martin Heinrich Klaproth, who chose the Latin word tellus, meaning “earth.” This name references Tellus, the Roman goddess who personified the Earth. Tellurium was discovered in gold ore from Transylvania.
A closely related element, Selenium (Se), was discovered by Swedish chemist Jöns Jacob Berzelius in 1817. Because of its chemical similarity to tellurium, Berzelius named the new element after the Moon. Selenium is derived from the Greek word selene, which refers to the Moon or the goddess Selene. This pairing highlights how chemical relationships can be reflected in mythological, celestial names.
Naming Conventions from Asteroids and Dwarf Planets
Celestial naming extends beyond major planets to include smaller solar system bodies, such as asteroids and dwarf planets. This is seen in the naming of Cerium (Ce), discovered in 1803. It was named after the dwarf planet Ceres, which had been discovered only two years earlier in 1801. Ceres was the first asteroid discovered and is the largest object in the asteroid belt between Mars and Jupiter.
Another example is Palladium (Pd), discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, the second asteroid found, discovered just the year before in 1802. These elements demonstrate a historical trend where the discovery of a new celestial body often inspires the name for a newly isolated element.