Neon (Ne) is a colorless, odorless, and chemically inert element belonging to the noble gas group on the periodic table. While rare on Earth, its most familiar characteristic is the brilliant reddish-orange glow it produces when an electrical current passes through it in a vacuum tube. Isolating this gas confirmed the existence of an entire family of unreactive elements hidden within the Earth’s atmosphere.
The Scientific Context: Separating Atmospheric Gases
The discovery of neon was made possible by advances in cryogenic technology, specifically the ability to liquefy air. This allowed scientists to cool air to extremely low temperatures, transforming it into a liquid. The different gaseous components could then be separated using fractional distillation. This process relies on the principle that each gas has a distinct, very low boiling point, causing components to vaporize and boil off at different temperatures as the liquid air is slowly warmed.
Sir William Ramsay and Lord Rayleigh first successfully used this method in 1894 to isolate Argon, the first noble gas found in the atmosphere. Ramsay and his colleague Morris Travers continued fractionally distilling the remaining atmospheric residue. This led to the discovery of Krypton, which boils off at a higher temperature than the other gases. The remaining fraction was a gas with an even lower boiling point, a substance previously undetectable by standard chemical means.
Pinpointing the Discovery Location and Time
The identification of neon occurred in May 1898 in the laboratory of Sir William Ramsay at University College London (UCL). Ramsay and Travers were working with the non-reactive residue left over after removing known components like nitrogen, oxygen, and argon from a sample of liquid air. Their goal was to isolate the final, lightest components remaining in their apparatus.
They froze a sample of pure argon using liquid air, then allowed it to evaporate under reduced pressure, collecting the very first portion of gas to boil off. This initial fraction had the lowest boiling point and contained the elusive new element. This small, highly volatile sample confirmed the element’s existence. The specialized equipment and precise temperature control necessary for this achievement made the UCL lab the birthplace of three new elements in a single summer.
Confirmation and Naming
To prove the isolated gas was a new element, Ramsay and Travers subjected the sample to spectroscopy. They sealed the gas in a vacuum discharge tube and applied a high voltage, a technique used to analyze the light spectrum emitted by energized elements. The moment the current was applied, the tube immediately flared with a brilliant scarlet-crimson light.
This unique light confirmed the gas was distinct from all other known elements, as each element has its own signature light spectrum. Ramsay named the new element “Neon,” taking inspiration from the Greek word néos, which translates to “new.” The element’s distinctive glow would eventually lead to its widespread use in signage.