Noble Gases: Properties

The elements belonging to Group 18 of the periodic table are noble gases. The noble gases are also known as the 'Inert Gases' or 'Aerogenes'. Noble gases are listed below:

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

Noble gases exist in the gaseous phase in normal temperature and pressure. The general configuration of the noble gases is ns2np6. Because of their stable electronic configuration, noble gases have very low reactivity, and because of their low reactivity, they do not form molecules easily and are generally found as mono-atomic gases.

Properties of Noble Gases

Properties of Helium

• The atomic number of Helium is 2, and is denoted as He.
• Helium is the first and the lightest of all noble gases.
• The atomic mass of Helium is 4.0002602 u.
• The electronic configuration of Helium is 1s².
• There are 2 electrons in the valence shell of Helium.
• Under the normal conditions for temperature and pressure, Helium exists as a colourless, odourless, tasteless, mono-atomic gas.
• In small concentrations, Helium is non-toxic.
• Under the normal conditions for temperature and pressure the density of Helium is 1.7186 grams per liter.
• The melting point of Helium is approximately -272° C.
• The boiling point of Helium is -268.9 °C

Properties of Neon

• The atomic number of Neon is 10, and is denoted as Ne.
• Neon is the second lightest of all the noble gases.
• The atomic mass of Neon is 20.1797 u.
• The electronic configuration of Neon is 2s² 2p⁶.
• There are 8 electrons in the valence shell of Neon.
• Under the normal conditions for temperature and pressure Neon exists as a colourless, odourless, mono-atomic gas.
• Under the normal conditions for temperature and pressure, the density of Neon is approximately 0.9 grams per liter.
• The melting point of Neon is approximately -248.59° C.
• The boiling point of Neon is -246° C

Properties of Argon

• The atomic number of Argon is 18, and is denoted as Ar.
• Argon is the 3rd most abundant gas in the earth's atmosphere.
• The atomic mass of Argon is 39.948u.
• The electronic configuration of Argon is 3s² 3p⁶.
• There are 8 electrons in the valence shell of Argon.
• Under the normal conditions for temperature and pressure, Argon exists as a colourless gas.
• When placed in an electric field Argon exhibits a violet or lilac-coloured glow.
• Under the normal conditions for temperature and pressure the density of Argon is approximately 1.784 grams per liter.
• The melting point of Argon is approximately -189.4° C.
• The boiling point of Argon is -185.8° C

Properties of Krypton

• The atomic number of Krypton is 36, and is denoted as Kr.
• The atomic mass of Krypton is 83.798 u.
• The electronic configuration of Krypton is 3d¹⁰ 4s² 4p⁶.
• Under the normal conditions for temperature and pressure, Krypton exists as a colourless, odourless, tasteless mono-atomic gas.
• Under the normal conditions for temperature and pressure, the density of Krypton is approximately 3.75 grams per liter.
• The melting point of Krypton is approximately -157.4° C.
• The boiling point of Krypton is -153.4 °C

Properties of Xenon

• The atomic number of Xenon is 54, and is denoted as Xe.
• The atomic mass of Xenon is 131.293 u.
• The electronic configuration of Xenon is 4d¹⁰ 5s² 5p⁶.
• Under the normal conditions for temperature and pressure, xenon exists as a colourless, odourless, mono-atomic gas.
• Under the normal conditions for temperature and pressure, the density of Xenon is approximately 5.89 grams per liter.
• The melting point of Xenon is approximately -111.75° C.
• The boiling point of Xenon is -108.1° C.

Properties of Radon

• The atomic number of Radon is 86, and is denoted as Rn.
• The atomic mass of Radon is 222.01758 u.
• The electronic configuration of Radon is 4f¹⁴ 5d¹⁰ 6s² 6p⁶.
• Under the normal conditions for temperature and pressure, Radon exists as a colourless, odourless, tasteless, mono-atomic gas.
• Radon is a radioactive gas. It is generated by the radioactive decay of Radium.
• Under the normal conditions for temperature and pressure, the density of Radon is approximately 9.73 grams per liter.
• The melting point of Neon is approximately -71° C.
• The boiling point of Radon is -61.7° C.