Neon

Neon is a colorless, chemically inert noble gas with atomic number 10. In electrical discharge tubes, it emits a characteristic bright reddish-orange light.

Atomic emission spectrum: A pattern of wavelengths emitted when excited atoms release energy as light. Neon’s reddish-orange glow consists of discrete wavelengths from transitions between atomic energy levels.
Noble gas: An element in Group 18, generally characterized by a filled outer electron shell and low chemical reactivity. Neon belongs to this family because its outer electron shell is filled.
Cryogenic refrigeration: Cooling methods that produce or use temperatures below about 150 kelvins. Liquid neon serves as a refrigerant in specialized systems because it boils at about 27 kelvins.
Morris Travers: A British chemist who discovered neon with William Ramsay in 1898. Travers helped isolate neon from liquefied air during the discovery.
Argon: A colorless noble gas with atomic number 18, abundant in Earth’s atmosphere. Argon is cheaper and more abundant, but its discharge color differs from neon’s.
Neon lamp: A gas-discharge lamp that produces light by passing current through low-pressure neon. It uses neon’s discharge directly to create a characteristic orange-red glow.
Neon atom: An atom with ten protons and, in its neutral form, ten electrons. Its electron arrangement determines neon’s characteristic spectrum and low reactivity.
Helium–neon laser: A gas laser that uses a helium-neon mixture to produce coherent light, commonly at 632.8 nanometers. Neon atoms provide the laser transitions; helium atoms transfer energy to them.
William Ramsay: A Scottish chemist whose work on noble gases earned him the 1904 Nobel Prize in Chemistry. Ramsay and Travers identified neon while investigating gases separated from air.
Helium: A colorless noble gas with atomic number 2 and the lowest boiling point of any element. Helium is lighter and far more volatile, while neon produces a stronger visible glow.

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