In many cultures, those who do not get angry when provoked, do not get influenced by anything and keep their dignity when in the presence of 'base' people are called 'noble'. Now what if a gas showed these traits? Would you call it a Noble Gas?
The Nobility of Elements
Some elements behave just like noble people - they do not react at all, whatever you do. There are two types - Noble Metals, and Noble Gases. Iridium, Platinum, and Gold are called Noble Metals. Helium, Neon, Argon, Krypton, Xenon and Radon are called Noble Gases.
Why Chemicals React
As you know, all elements have electrons in their atoms. Electrons love being in pairs. If an electron is alone, it'll be unhappy till it finds another one. If an electron finds another lonely electron on another atom, it will make its atom join up with the other atom. That's how chemical reactions happen.
Some chemicals like sodium have extra electrons. There are other chemicals like oxygen or chlorine, which desperately need an electron or two. So when they meet, they react immediately. Because of this, they are called 'base' elements.
So why are Noble Gases different? Every electron in an atom of a Noble Gas has a partner. There are no loose electrons, and no places to fill either. Because of this, Noble Gases react with nothing. Actually, no. If you make a Noble Gas very hot or put too much pressure on it, the electron pairs break up and they become reactive. But these things don't happen in nature, except inside the cores of giant stars.
Xenon dissolves in fatty substances, like the lipid layer that makes up the membranes of cells. Therefore, it's used as an anaesthetic, since it easily gets into the lipid layer and shuts down nerve cell function. Xenon is quite safe, and you can wake up much faster than with any other anaesthetic.
Are Noble Gases any use at all?
Most elements are useful, because they can form complex chemicals with other elements. But noble gases are not completely useless. In fact they have a few fun uses.
In birthday parties, you'll have seen balloons that keep floating. That's because they're filled with helium instead of air. If you've seen a TV show about coral reefs, you'll have seen divers swimming with cylinders on their backs. The cylinders are filled with helium mixed with oxygen. That's because it makes the cylinder lighter, and it's easier for the diver to breathe.
We know how wonderful neon lights are. Neon gas is filled in these tubes to give a bright light. And if you coat the tube with different things, you get neon lights of different colours. Other Noble Gases are also used in lamps.
What makes the picture in IMAX theatres better? It's xenon! Xenon is filled in the lamp that's used to project the film on the screen. Like xenon, argon and krypton are also used in different kinds of electric lamps as a filling instead of air. Laser beams made from argon, krypton or xenon lamps are used by surgeons to remove cholesterol blocking the arteries and to correct eye problems.