|
|
Atomic Number: |
10 |
Melting Point: | -258.59 ºC | |
| Atomic Symbol: | Ne | Boiling Point: | -246.08 ºC | ||
| Atomic Weight: | 20.179 amu | Density: | 0.8999
kg/m 3 |
||
| Atomic Radius: |
.848 pm |
Oxidation States: | -- | ||
| Covalent Radius: | 69 pm | Electron Configuration: | [He]2s22p6 | ||
| van der Waals Radius: |
154 pm |
State of Matter: | gas (nonmagnetic) |
(Gr. neos: new) Discovered by Ramsay and Travers in 1898.
Neon is the second-lightest noble gas. In a vacuum discharge tube, neon glows reddish orange.
It has over 40 times more refrigerating capacity per unit volume than liquid helium and more than three times that of liquid hydrogen. It is compact, inert, and is less expensive than helium when it meets refrigeration requirements.
Of all the rare gases, the discharge of neon is the most intense at ordinary voltages and currents.
Neon is a very inert element, however, it has been reported to form a compound with fluorine. It is still questionable if true compounds of neon exist, but evidence is mounting in favor of their existence. The ions, Ne+, (NeAr)+, (NeH)+, and (HeNe+) are known from optical and mass spectrometric studies. Neon also forms an unstable hydrate.
Neon is usually found in the form of a gas with molecules consisting of a single Neon atom. It is a rare gaseous element present in the atmosphere to the extent of 1 part in 65,000 of air. It is obtained by liquefaction of air and separated from the other gases by fractional distillation.
Although neon advertising signs account for the bulk of its use, neon also functions in high-voltage indicators, lightning arrestors, wave meter tubes, and TV tubes. Neon and helium are used in making gas lasers. Liquid neon is now commercially available and is finding important application as an economical cryogenic refrigerant.
Liquefied neon is commercially used as an economical cryogenic regrigerant.
Neon has three stable isotopes: Ne-20 (90.48%), Ne-21 (0.27%) and Ne-22 (9.25%). Ne-21 and Ne-22 are nucleogenic and their variations are well understood. In contrast, Ne-20 is not known to be nucleogenic and the causes of its variation in the Earth have been hotly debated. The principal nuclear reactions which generate neon isotopes are neutron emission, alpha decay reactions on Mg-24 and Mg-25, which produce Ne-21 and Ne-22, respectively.
Six other unstable isotopes are known.
Neon gas is not toxic at normal temperature and
pressure. However, like other inert gases such as nitrogen and argon, neon is a
simple asphyxiant. Simple asphyxiants can displace oxygen in the air, especially
in a confined space. The lack of oxygen then causes the victim to suffocate.
Proper ventilation is required.
