Noble Gases Properties, Uses and Sources

Noble Gas Element Group

Laser beams
The noble gases are used in lamps and lasers, such as this krypton laser. They are also used to form inert atmospheres. Charles O'Rear / Getty Images

The right column of the periodic table contains seven elements known as the inert or noble gases. Learn about the properties of the noble gas group of elements.

Key Takeaways: Noble Gas Properties

  • The noble gases are group 18 on the periodic table, which is the column of elements on the right side of the table.
  • There are seven noble gas elements: helium, neon, argon, krypton, xenon, radon, and oganesson.
  • Noble gases are the least reactive chemical elements. They are nearly inert because the atoms have a full valence electron shell, with little tendency to accept or donate electrons to form chemical bonds.

Location and List of the Noble Gases on the Periodic Table

The noble gases, also known as the inert gases or rare gases, are located in Group VIII or IUPAC group 18 of the periodic table. This is the column of elements along the far right side of the periodic table. This group is a subset of the nonmetals. Collectively, the elements are also called the helium group or the neon group. The noble gases are:

  • Helium (He)
  • Neon (Ne)
  • Argon (Ar)
  • Krypton (Kr)
  • Xenon (Xe)
  • Radon (Rn)
  • Oganesson (Og)

With the exception of oganesson, all of these elements are gases at ordinary temperature and pressure. There haven't been enough atoms of oganesson to know its phase for certain, but most scientists predict it will be a liquid or solid.

Both radon and oganesson consist only of radioactive isotopes.

Noble Gas Properties

The noble gases are relatively nonreactive. In fact, they are the least reactive elements on the periodic table. This is because they have a complete valence shell. They have little tendency to gain or lose electrons. In 1898, Hugo Erdmann coined the phrase "noble gas" to reflect the low reactivity of these elements, in much the same way as the noble metals are less reactive than other metals. The noble gases have high ionization energies and negligible electronegativities. The noble gases have low boiling points and are all gases at room temperature.

Summary of Common Properties

  • Fairly nonreactive
  • Complete outer electron or valence shell (oxidation number = 0)
  • High ionization energies
  • Very low electronegativities
  • Low boiling points (all monatomic gases at room temperature)
  • No color, odor, or flavor under ordinary conditions (but may form colored liquids and solids)
  • Nonflammable
  • At low pressure, they will conduct electricity and fluoresce

Uses of the Noble Gases

The noble gases are used to form inert atmospheres, typically for arc welding, to protect specimens, and to deter chemical reactions. The elements are used in lamps, such as neon lights and krypton headlamps, and in lasers. Helium is used in balloons, for deep-sea diving air tanks, and to cool superconducting magnets.

Misconceptions About the Noble Gases

Although the noble gases have been called the rare gases, they aren't particularly uncommon on Earth or in the universe. In fact, argon is the 3rd or 4th most abundant gas in the atmosphere (1.3% by mass or 0.94% by volume), while neon, krypton, helium, and xenon are notable trace elements.​

For a long time, many people believed the noble gases to be completely nonreactive and unable to form chemical compounds. Although these elements don't form compounds readily, examples of molecules containing xenon, krypton, and radon have been found. At high pressure, even helium, neon, and argon participate in chemical reactions.

Sources of the Noble Gases

Neon, argon, krypton, and xenon all are found in air and are obtained by liquefying it and performing fractional distillation. The major source of helium is from the cryogenic separation of natural gas. Radon, a radioactive noble gas, is produced from the radioactive decay of heavier elements, including radium, thorium, and uranium. Element 118 is a man-made radioactive element, produced by striking a target with accelerated particles. In the future, extraterrestrial sources of noble gases may be found. Helium, in particular, is more abundant on larger planets than it is on Earth.

Sources

  • Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.). Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
  • Lehmann, J (2002). "The Chemistry of Krypton". Coordination Chemistry Reviews. 233–234: 1–39. doi:10.1016/S0010-8545(02)00202-3
  • Ozima, Minoru; Podosek, Frank A. (2002). Noble Gas Geochemistry. Cambridge University Press. ISBN 0-521-80366-7.
  • Partington, J. R. (1957). "Discovery of Radon". Nature. 179 (4566): 912. doi:10.1038/179912a0
  • Renouf, Edward (1901). "Noble gases". Science. 13 (320): 268–270.