# 12.9: Group VIIIA- Noble Gases

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The properties of the noble gases are summarized in the table below. The noble gases have a complete octet of electrons ns2np6 or just ns2 for helium, leaving them with little chemical reactivity. Sure enough,the ionization energies of He and Ne are greater than 2000 kJ mol–1, and it is unlikely that these noble gases will ever be induced to form chemical bonds. The same probably applies to Ar. Kr and especially Xe do form compounds though, which was discussed in the halogens section, and Rn might be expected to be even more reactive. Rn is radioactive, however, and study of its chemistry is difficult.

Table $$\PageIndex{1}$$ Properties of the Group VIII Elements.
Element Symbol

Electron

Configuration

Usual

Oxidation State

Helium He 1s2 0

...

Neon Ne [He]2s22p6 0

...

Argon Ar [Ne]3s23p6 0

...

Krypton Kr [Ar]4s23d104p6 +2

110

Xenon Xe [Kr]5s24d105p6 +8, +6, +4, +2 130
Symbol Ionization Energy/MJ mol–1

Density/

g cm–3

Electro-

negativity

Melting

Point (in °C)

First Second
He 2.379 5.257 0.179 ...

-272

Ne 2.087 3.959 0.901 ... -249
Ar 1.527 2.672 1.78 ... -190
Kr 1.357 2.374 3.74 2.6 -157
Xe 1.177 2.053 5.86 2.4 -112

Because of the lack of reactivity of the noble gases, they are often used when an nonreactive atmosphere is needed, such as in welding. Due to their low boiling points, noble gases are also cryogens in their liquid forms. One familiar use of helium is in balloons and blimps, since it is buoyant in the atmosphere, and unlike hydrogen, nonreactive. Another familiar use is as lighting in gas discharge lamps. Referred to popularly as neon lights, they can contain other noble gases, or mixtures of the gases.

This page titled 12.9: Group VIIIA- Noble Gases is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Ed Vitz, John W. Moore, Justin Shorb, Xavier Prat-Resina, Tim Wendorff, & Adam Hahn.