neon

/nee"on/, n.

1. Chem. a chemically inert gaseous element occurring in small amounts in the earth's atmosphere, used chiefly in a type of electrical lamp. Symbol: Ne; at. wt.: 20.183; at. no.: 10; density: 0.9002 g/l at 0°C and 760 mm pressure.

2. See neon lamp.

3. a sign or advertising sign formed from neon lamps.

adj.

4. using or containing the gas neon.

5. made of or formed by a neon lamp or lamps: a neon sign.

6. of, pertaining to, or characteristic of a tawdry urban district or of gaudy nighttime entertainment.

[1895-1900; < NL < Gk néon new, recent (neut. of néos); see -ON¹]

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Chemical element, chemical symbol Ne, atomic number 10.

One of the noble gases, neon is colourless, odourless, tasteless, and completely unreactive. It occurs in minute amounts in the atmosphere and is obtained by fractional distillation of liquefied air. When under low pressure, it glows a bright orange-red if an electric current is passed through it. It was discovered in 1898, and since the 1920s its chief use has been in luminous tubes and bulbs.

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▪ chemical element

  chemical element, inert gas of Group 18 (noble gases (noble gas)) of the periodic table (periodic law), used in electric signs and fluorescent lamps (fluorescent lamp). Colourless, odourless, tasteless, and lighter than air, neon gas occurs in minute quantities in Earth's (Earth) atmosphere and trapped within the rocks of Earth's crust. Though neon is about 3¹/₂ times as plentiful as helium in the atmosphere, dry air contains only 0.0018 percent neon by volume. This element is more abundant in the cosmos than on Earth. Neon liquefies at −246.048 °C (−411 °F) and freezes at a temperature only 2¹/₂° lower. When under low pressure, it emits a bright orange-red light if an electrical current (electric current) is passed through it. This property is utilized in neon signs (which first became familiar in the 1920s), in some fluorescent and gaseous conduction lamps, and in high-voltage testers. The name neon is derived from the Greek word neos, “new.”

      Neon was discovered (1898) by the British chemists Sir William Ramsay (Ramsay, Sir William) and Morris W. Travers as a component of the most volatile fraction of liquefied crude argon obtained from air. It was immediately recognized as a new element by its unique glow when electrically stimulated. Its only commercial source is the atmosphere, in which it is 18 parts per million by volume. Because its boiling point is −246 °C (−411 °F), neon remains, along with helium and hydrogen, in the small fraction of air that resists liquefaction upon cooling to −195.8 °C (−320.4 °F, the boiling point of liquid nitrogen). Neon is isolated from this cold, gaseous mixture by bringing it into contact with activated charcoal, which adsorbs the neon and hydrogen; removal of hydrogen is effected by adding enough oxygen to convert it all to water, which, along with any surplus oxygen, condenses upon cooling. Processing 88,000 pounds of liquid air will produce one pound of neon.

      No stable chemical compounds of neon have been observed. Molecules (molecule) of the element consist of single atoms (atom). Natural neon is a mixture of three stable isotopes (isotope): neon-20 (90.92 percent); neon-21 (0.26 percent); and neon-22 (8.82 percent). Neon was the first element shown to consist of more than one stable isotope. In 1913, application of the technique of mass spectrometry revealed the existence of neon-20 and neon-22. The third stable isotope, neon-21 was detected later. Twelve radioactive isotopes (radioactive isotope) of neon also have been identified.

atomic number

10

atomic weight

20.183

melting point

−248.67 °C (−415.5 °F)

boiling point

−246.048 °C (−411 °F)

density (1 atm, 0° C)

0.89990 g/litre

oxidation state

0

electronic config.

1s²2s²2p⁶

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