Neon

Neon, 10Ne
Neon
Appearancecolorless gas exhibiting an orange-red glow when placed in an electric field
Standard atomic weight Ar°(Ne)
Neon in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
He
↑
Ne
↓
Ar
fluorine ← neon → sodium
Atomic number (Z)10
Groupgroup 18 (noble gases)
Periodperiod 2
Block  p-block
Electron configuration[He] 2s2 2p6
Electrons per shell2, 8
Physical properties
Phase at STPgas
Melting point24.56 K ​(−248.59 °C, ​−415.46 °F)
Boiling point27.104 K ​(−246.046 °C, ​−410.883 °F)
Density (at STP)0.9002 g/L
when liquid (at b.p.)1.207 g/cm3[3]
Triple point24.556 K, ​43.37 kPa[4][5]
Critical point44.4918 K, 2.7686 MPa[5]
Heat of fusion0.335 kJ/mol
Heat of vaporization1.71 kJ/mol
Molar heat capacity20.79[6] J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 12 13 15 18 21 27
Atomic properties
Oxidation statescommon: (none)
0[7]
Ionization energies
  • 1st: 2080.7 kJ/mol
  • 2nd: 3952.3 kJ/mol
  • 3rd: 6122 kJ/mol
  • (more)
Covalent radius58 pm
Van der Waals radius154 pm
Spectral lines of neon
Other properties
Natural occurrenceprimordial
Crystal structure ​face-centered cubic (fcc) (cF4)
Lattice constant
a = 453.77 pm (at triple point)[8]
Thermal conductivity49.1×10−3 W/(m⋅K)
Magnetic orderingdiamagnetic[9]
Molar magnetic susceptibility−6.74×10−6 cm3/mol (298 K)[10]
Bulk modulus654 GPa
Speed of sound435 m/s (gas, at 0 °C)
CAS Number7440-01-9
History
Namingfrom the Greek word νέον, meaning 'new'
PredictionWilliam Ramsay (1897)
Discovery and first isolationWilliam Ramsay & Morris Travers[11][12] (1898)
Isotopes of neon
Main isotopes[13] Decay
abun­dance half-life (t1/2) mode pro­duct
20Ne 90.5% stable
21Ne 0.27% stable
22Ne 9.25% stable

Neon is a chemical element; it has symbol Ne and atomic number 10. It is the second noble gas in the periodic table.[14] Neon is a colorless, odorless, inert monatomic gas under standard conditions, with approximately two-thirds the density of air.

Neon was discovered in 1898 alongside krypton and xenon, identified as one of the three remaining rare inert elements in dry air after the removal of nitrogen, oxygen, argon, and carbon dioxide. Its discovery was marked by the distinctive bright red emission spectrum it exhibited, leading to its immediate recognition as a new element. The name neon originates from the Greek word νέον, a neuter singular form of νέος (neos), meaning 'new'. Neon is a chemically inert gas; although neon compounds do exist, they are primarily ionic molecules or fragile molecules held together by van der Waals forces.

The synthesis of most neon in the cosmos resulted from the nuclear fusion within stars of oxygen and helium through the alpha-capture process. Despite its abundant presence in the universe and Solar System—ranking fifth in cosmic abundance following hydrogen, helium, oxygen, and carbon—neon is comparatively scarce on Earth. It constitutes about 18.2 ppm of Earth's atmospheric volume and a lesser fraction in the Earth's crust. The high volatility of neon and its inability to form compounds that would anchor it to solids explain its limited presence on Earth and the inner terrestrial planets. Neon's high volatility facilitated its escape from planetesimals under the early Solar System's nascent Sun's warmth.

Neon's notable applications include its use in low-voltage neon glow lamps, high-voltage discharge tubes, and neon advertising signs, where it emits a distinct reddish-orange glow.[15][16] This same red emission line is responsible for the characteristic red light of helium–neon lasers. Although neon has some applications in plasma tubes and as a refrigerant, its commercial uses are relatively limited. It is primarily obtained through the fractional distillation of liquid air, making it significantly more expensive than helium due to air being its sole source.

  1. ^ "Standard Atomic Weights: Neon". CIAAW. 1985.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (4 May 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ Hammond, C. R. (2000). The Elements, in Handbook of Chemistry and Physics 81st edition (PDF). CRC press. p. 19. ISBN 0849304814.
  4. ^ Preston-Thomas, H. (1990). "The International Temperature Scale of 1990 (ITS-90)". Metrologia. 27 (1): 3–10. Bibcode:1990Metro..27....3P. doi:10.1088/0026-1394/27/1/002.
  5. ^ a b Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, Florida: CRC Press. p. 4.122. ISBN 1-4398-5511-0.
  6. ^ Shuen-Chen Hwang, Robert D. Lein, Daniel A. Morgan (2005). "Noble Gases". in Kirk Othmer Encyclopedia of Chemical Technology, pages 343–383. Wiley. doi:10.1002/0471238961.0701190508230114.a01.pub2
  7. ^ Ne(0) has been observed in Cr(CO)5Ne; see Perutz, Robin N.; Turner, James J. (August 1975). "Photochemistry of the Group 6 hexacarbonyls in low-temperature matrices. III. Interaction of the pentacarbonyls with noble gases and other matrices". Journal of the American Chemical Society. 97 (17): 4791–4800. Bibcode:1975JAChS..97.4791P. doi:10.1021/ja00850a001.
  8. ^ Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
  9. ^ Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0486-5.
  10. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  11. ^ Ramsay, William; Travers, Morris W. (1898). "On the Companions of Argon". Proceedings of the Royal Society of London. 63 (1): 437–440. doi:10.1098/rspl.1898.0057. ISSN 0370-1662. S2CID 98818445.
  12. ^ "Neon: History". Softciências. Retrieved 27 February 2007.
  13. ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  14. ^ Group 18 refers to the modern numbering of the periodic table. Older numberings described the rare gases as Group 0 or Group VIIIA (sometimes shortened to 8). See also Group (periodic table).
  15. ^ Coyle, Harold P. (2001). Project STAR: The Universe in Your Hands. Kendall Hunt. p. 464. ISBN 978-0-7872-6763-6.
  16. ^ Kohmoto, Kohtaro (1999). "Phosphors for lamps". In Shionoya, Shigeo; Yen, William M. (eds.). Phosphor Handbook. CRC Press. p. 940. ISBN 978-0-8493-7560-6.
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