Biology / Unit 1 Bio 0125 short lesson, about 20 seconds
Electron Shells and the Octet Rule
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The idea
Electrons occupy shells at increasing distances from the nucleus; the octet rule favors eight electrons in an atom's outer shell.
In practice
Neon holds eight electrons in its outer shell and rarely reacts; sodium holds only one and readily gives it up.
Where people slip
The octet rule is a stability rule, not a hard limit — the innermost shell is stable at only two electrons.
Your place on the trail
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