The Noble Gases
We love the noble gases. Some scientists used to call
them the inert gases. It didn't really work because there are a few
other gases that are basically inert but not noble gases. Nitrogen (N2)
might be considered an inert gas, but it is not a noble gas. The noble
gases are another family of elements, and all of them are located in the
far right column of the periodic table.
For all of you budding chemists, the far right is also known as Group
Zero (Group 0) or Group Eighteen (Group XVIII). This family has the
happiest elements of all.
Why Are They Happy?
Using the Bohr description of electron shells, happy atoms have full shells. All of the noble gases have full outer shells with eight electrons. Oh, wait! That's not totally correct. At the top of the noble gases is little helium
(He), with a shell that is full with only two electrons. The fact that
their outer shells are full means they are quite happy and don't need to
react with other elements. In fact, they rarely combine with other
elements. That non-reactivity is why they are called inert.
Who's in the Family?
All of the elements in Group Zero are noble gases. The
list includes helium, neon (Ne), argon (Ar), krypton (Kr), xenon (Xe),
and radon (Rn). Don't think that, because these elements don't like to
react, we don't use them. You will find noble gases all over our world.
Neon is used in advertising signs. Argon is used in light bulbs. Helium
is used in balloons and to cool things. Xenon is used in headlights for
new cars. Because of their chemical properties, these gases are also
used in the laboratory to help stabilize reactions that would usually
proceed too quickly. When you move down the periodic table, as the atomic numbers increase, the elements become rarer. They are not just rare in nature, but rare as useful elements, too.
But Wait, They Do Bond!
Some do. As of about 40 years ago, scientists have been able to make
some compounds with noble gases. Some have been used in compounds to
make explosives, and others just form compounds in a lab. The thing to
remember is that they were forced. When going about their natural lives,
you will never (well, never say never, because there may be an
exception) find the noble gases bonded to other elements.
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