Inert

In chemistry, the term inert is used to describe something that is not chemically active. The noble gases were described as being inert because they did not react with the other elements or themselves. Now scientists know that the reason that inert gases are completely inert to basic chemical reactions (such as combustion), for example, is because their outer valence shell is completely filled with electrons. With a filled outer valence shell, an inert atom is not able to acquire or lose an electron, and is therefore not able to participate in any chemical reactions.

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