Reference Terms
from Wikipedia, the free encyclopedia


Argon is a chemical element in the periodic table.

It has the symbol Ar and atomic number 18.

The third noble gas, in group 18, argon makes up about 1% of the Earth's atmosphere, making it the most common noble gas on Earth.

Note:   The above text is excerpted from the Wikipedia article "Argon", which has been released under the GNU Free Documentation License.
Related Stories

Matter & Energy News
May 27, 2017

Latest Headlines
updated 12:56 pm ET