What is Xenon? - Definition, Uses & Facts

Instructor: Kelsey Skodje

Kelsey has taught college chemistry and biochemistry and has a Ph.D. in bioinorganic chemistry.

Xenon is an element that exists as a gas at most temperatures and is not very reactive. This lesson looks at some general information about xenon, as well as some of its useful applications.

What is Xenon?

Xenon (Xe) is a colorless, odorless gas and is a member of the noble gas family of elements, which also includes helium, neon, argon, and krypton. The noble gases are all very un-reactive, or inert. Because of this, they usually won't be found participating in chemical reactions and forming new compounds.

The name xenon is pronounced ZEE-non and comes from the Greek word for 'stranger'. Its atomic symbol is Xe, and on the periodic table of elements, xenon can be found in Group 18 and Period 5. The rest of the noble gases are also found in Group 18. Xenon's atomic number is 54, which means it has 54 protons in its nucleus. Xenon also has nine stable isotopes. Xenon isotopes are atoms of xenon that have the same number of protons (54) but varying numbers of neutrons.

Periodic table of the elements. Find xenon in the right-most blue column.
Periodic Table of the Elements

Xenon was discovered by William Ramsay and Morris Travers in 1898. At the time, it was thought to be completely un-reactive, but in 1962 Neil Bartlett disproved this by forming a compound consisting of xenon, fluoride, and platinum. Today, there are a number of useful applications of xenon and xenon compounds. Because Xe is not very abundant in our atmosphere, it is more expensive than most other gases and so is used in specialized applications.

Properties of Xenon

One of xenon's most important properties is its inertness. The reason xenon doesn't react easily is that it's so stable on its own. This stability is caused by its full set of valence electrons--these are the electrons farthest from an atom's nucleus and are the only electrons that participate in chemical bonding. When an atom does not have a full set of valence electrons it will bind to other atoms in order to complete its set. Thus, xenon's full set of valence electrons allows it to exist comfortably on its own.

Another feature of xenon is that it's heavier than most of the gases in the air we breathe, which mostly contains nitrogen and oxygen. Helium, another noble gas, is lighter than air, which is why helium balloons float. However, a balloon filled with xenon would quickly fall to the ground. We can see that xenon is heavier than helium by comparing their atomic numbers: xenon is heavier because it has an atomic number of 54 and helium's is 2 (so xenon has 52 more protons and therefore much more mass).

Xenon exists as a gas at room temperature, or approximately 23°C. Xenon's boiling point is about 165.1 K (around -108.1°C or -162.6°F). At temperatures below its boiling point, xenon becomes a liquid. Once temperatures reach its melting point, which is about 161.4 K (approximately -111.8°C or -169.2°F), Xe exists as a light-blue solid.

Uses of Xenon

Xe can be used in certain types of lamps, due to the blue glow it emits when electricity is applied. This is similar to how neon lights like the ones you see in Las Vegas work. These lamps can be used to kill bacteria, which could be extremely helpful in disinfecting hospital rooms and equipment.

Xenon emits a blue glow when electricity is applied.
Xenon Ion Spectral Radiation

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