What is Neon?

Neon is a colorless, odorless gas that becomes a bright orange-red glow when electricity is applied to it. It is a noble gas and belongs to group 18 of the periodic table, along with argon, krypton, xenon, and radon. Neon is not toxic but may asphyxiate by denying oxygen, so it needs to be stored in a sealed container and kept away from sources of heat or fire.

Chemists Ramsay and Travers discovered neon in 1898, along with krypton and xenon, after freezing an air sample of argon and running high voltage through it to make it glow. They christened the new element after the Greek word neos, meaning “new,” and it is now the fourth most abundant element in the universe, according to the Jefferson Laboratory. On Earth, it makes up 0.0018 percent of the atmosphere.

Like all noble gases, neon does not react with most other elements, but it does form molecular ions and excimers. (Molecular ions are atoms with full or partial octets of electrons, while excimers consist of short-lived dimeric molecules that contain one atom with a full octet and another atom without a full octet.)

A classic neon sign is a glass tube that has electrodes at both ends—one negative and one positive—and a transformer that supplies alternating current to the tubes, making them glow with a steady orange-red light when electricity passes through them. These signs are often used in outdoor advertising, and they can last up to 20 years when properly maintained.