Atoms whose outer electron shells contain eight electrons tend to do what

In general, atoms are most stable, least reactive, when their outermost electron shell is full. Most of the elements important in biology need eight electrons in their outermost shell in order to be stable, and this rule of thumb is known as the octet rule.

Explanation:

Atoms with a full valence shell are non reactive. Most shells have room for 8 electrons, so these atoms described are most likely noble gases. The answer is more or less nothing. They do not react because they have no electronegativity and no "extra" electrons

Explanation:

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