Skip to content
Science, Maths & Technology
  • Video
  • 5 mins
  • Level 1: Introductory

Noble gases

Updated Tuesday 17th July 2007

Noble gases. Some balloons. A rooftop. Watch what happens...

Video

Copyright The Open University

Text version

Here are five of the six noble gases: helium, neon, argon, kypton and xeon. They're all colourless and transparent. Krypton and xeon form compounds only with difficulty. Helium, neon and argon don't form compounds at all.

As we descend the group in the periodic table the atomic number and relative atomic mass increases. The gasses get denser.

Helium - helium is lighter than air. Neon is just lighter. Argon and krypton - I've just got to unstick these from the anchorage... Argon and krypton are both heavier than air. And xeon, xeon is the heaviest of the lot, you've heard of a lead balloon, well this is it.

The science

The noble gases, in order of their density, are helium, neon, argon, krypton, xenon and radon. They are called noble gases because they are so majestic that, in general, they don’t react with anything. For this reason they are also known as inert gases.

The noble gases are present in the atmosphere in small amounts:

  • 0.934% Argon
  • 0.0018% Neon
  • 0.00052% Helium
  • 0.00011% Krypton
  • 0.000009% Xenon

Most of the noble gases are extracted from the air, except for helium. Helium is a product of radioactive decay (the alpha particle) and is found naturally in rocks. Most of the helium used nowadays comes from natural gas, of which it comprises 7%.

Helium, the lightest, is used for filling party balloons. It is also mixed with oxygen to create a mixture that divers can breathe at depth – the helium is not very soluble in the blood so it avoids the “bends”.

Neon is probably most famous for neon signs – a tube containing neon gas through which a current is passed which causes the gas to give out light. When mixed with helium it is used to make helium-neon lasers.

Argon is used as the inert atmosphere in many light bulbs – an electric current is passed through a wire to heat it up so that it gets so hot it emits light. At these temperatures the metal would react with any oxygen present which is why an inert gas is needed.

Krypton is used to produce white light for photography – again an electrical current is passed through the gas so it emits light.

Xenon is again used in high quality lamps such as those used in lighthouses and in lasers.

Radon is a radioactive element. Radon gas is formed by decay of other radioactive elements and the concentration in the environment depends upon the types of rocks on which you live. For example, the granite in Dartmoor contains small amounts of uranium that forms radon, which can accumulate in buildings and drinking water. This leads to an increased risk of cancer.

 

For further information, take a look at our frequently asked questions which may give you the support you need.

Have a question?

Other content you may like

Elements of the Periodic Table Creative commons image Icon The Open University under Creative Commons BY-NC-SA 4.0 license activity icon

Science, Maths & Technology 

Elements of the Periodic Table

Explore the impact of chemical elements on our bodies, our world, and see how they changed the course of history

Activity
Science experiment: The density tower Creative commons image Icon The Open University under Creative Commons BY-NC-SA 4.0 license video icon

Science, Maths & Technology 

Science experiment: The density tower

In this video, the OU's Janet Sumner shows you how to conduct a simple density tower experiment using everyday household liquids.

Video
5 mins
article icon

Science, Maths & Technology 

Fireworks Challenge Glossary

Some of the key terms associated with making fireworks

Article
Separate coloured ink with this experiment article icon

Science, Maths & Technology 

Separate coloured ink with this experiment

Did you know your black biro isn't black and your green felt tip isn't green? Don't believe this? Try this chromatography experiment.

Article
Hand warmers Copyrighted image Icon Copyright: Production team article icon

Science, Maths & Technology 

Hand warmers

Information on how to make hand warmers, one of the scientists' challenges on the BBC/OU series Rough Science 3

Article
Dante's Peak Copyrighted image Icon Copyright: BBC article icon

Science, Maths & Technology 

Dante's Peak

Would an acid-filled lake really not float Pierce Brosnan's boat, or is the science of Dante's Peak off-kilter?

Article
Make a waterproof tent Copyrighted image Icon Copyright: Production team article icon

Science, Maths & Technology 

Make a waterproof tent

How would you set about waterproofing a tent if you only had what was to hand, your wits, and science to help?

Article
Inside power Copyrighted image Icon Copyright: Production team article icon

Science, Maths & Technology 

Inside power

Flames are an integral part of burning and combustion, and clearly provide strong evidence that chemical reactions may involve large energy changes. But why is a flame formed? What are its properties? This course extract sets out to provide some answers to these questions. In the process, we discover quite a lot about the way in which many chemical reactions actually occur

Article
Lanolin, Wool and Hand Cream Copyrighted image Icon Copyright: Production team article icon

Science, Maths & Technology 

Lanolin, Wool and Hand Cream

Instructions on how to make hand cream out of sheep's wool, one of the scientists' challenges on the BBC/OU series Rough Science 3

Article