noble gas
The properties of the noble gases can be well explained by modern theories of atomic structure: their outer shell of valence electrons is considered to be “full”, giving them little tendency to participate in chemical reactions, and only a few hundred noble gas compounds have been prepared. [1]
Noble Gases are elements that are in a gaseous state at room temperature. [2]
The noble gases, from the German word Edelgas, are a family of nonreactive monoatomic gases found on the far right of the periodic table. [3]
The noble gases are the chemical elements in group 18 of the periodic table. [4]
The essential condition for their formation is that the guest (noble gas) atoms should be of appropriate size to fit in the cavities of the host crystal lattice. [5]
The six noble gases are found in group 18 of the periodic table. [6]
Along the extreme right-hand column of the periodic table of elements is a group known as the noble gases: helium, neon, argon, krypton, xenon, and radon. [7]
The noble gases are a group of chemical elements with very similar properties: under standard conditions, they are all odorless, colorless, monatomic gases, with a very low chemical reactivity. [1]
For all of the Noble Gases their outer shells are filled with 8 electrons except for Helium which has only 2 in the first shell. [2]
Other characteristics of the noble gases are that they all conduct electricity, fluoresce, are odorless and colorless, and are used in many conditions when a stable element is needed to maintain a safe and constant environment. [4]
Noble gas compounds are chemical compounds that include an element from Group 18 of the periodic table, the noble gases. [5]
Any of the elements in Group O of the periodic table, including helium, neon, argon, krypton, xenon, and radon, which are monatomic and with limited exceptions chemically inert. [7]
Helium is typically separated from natural gas, and radon is usually isolated from the radioactive decay of dissolved radium compounds. [1]
Helium, the most common noble gas, makes up about 1/4th of all atoms in the universe. [3]
It was initially believed that the noble gases could not form compounds due to their full valence shell of electrons that rendered them very chemically stable and unreactive. [5]
Sources:
[1] Noble gas - Wikipedia, the free encyclopedia (en.wikipedia.org/wiki/Noble_gas)
[2] Noble gas - CreationWiki, the encyclopedia of creation science (creationwiki.org/Noble_gas)
[3] What is a Noble Gas? (www.wisegeek.com/
[4] Noble gas (www.sciencedaily.com/articles/n/
[5] Noble gas compound - Wikipedia, the free encyclopedia (en.wikipedia.org/wiki/
[6] Chemical Elements.com - Noble Gases (www.chemicalelements.com/groups/
[7] noble gas: Definition from Answers.com (www.answers.com/topic/noble-gas)