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History and Production
From Greek neo, meaning new. It was discovered by W. Ramsey and M.W. Travers in 1898. It can be isolated from liquefaction and fractional distillation of air. It is used in making advertizing signs, lightning arrestors, TV tubes and gas laser (Ne laser).
The liquid is used as a cryogenic refrigerant.
Physical Data
The gas is generally inert and exist as a monoatomic entity in atmosphere to an extent of 1 part in 65000 of air. It is colorless, odorless and tasteless. In a vacuum discharge tube, neon glows reddish orange.
Interatomic distance: 300.0 pm (van der Waal diameter)
Melting point: -248.67°C
Boiling point: -246.08°C
Thermal conductivity/Wm-1K-1: 00.0461 (0°C), 0.0493 (27°C)
Density/kgm-3: 1444 (m.p.), 1207.3 (b.p.), 0.89994 (0°C)
Standard Thermodynamic Data (atomic gas)
Enthalpy of formation: 0 kJ/mol
Gibbs free energy of formation: -
Entropy: 146.3 J/mol K
Heat capacity: 20.8 J/mol K
Electronic data
Electronic configuration: [He] 2s2 2p6 = [Ne]
Term symbol: 1S0
Electron affinity: (not stable) Electronegativity (Pauline): -
Ionization energy (first, second, third): 2080.67, 3952.36, 6122.0 kJ/mol
Chemical property
Neon's outer-most electron shell has already achieved the most stable configuration and hence the atom is particularly resistant to chemical reaction.
There are no known stable compound of neon. There are some evidence for the existence of neon compounds, such as that with fluorine, and may occur as transient species.
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