How many electrons can the third shell hold?
Quick Answer
In basic chemistry, the third shell is often taught as holding 8 electrons, but in the full quantum model it can hold up to 18. That is why chemistry becomes more complex after the second period.
The Full Story
The third electron shell is often simplified in school chemistry as holding 8 electrons, but the full quantum-mechanical maximum is 18. The reason is that the shell contains multiple subshells with different capacities. This is one reason the periodic table does not follow a simple two-row pattern after the first two periods. Elements in the third period, such as sodium, magnesium, and chlorine, are often used to illustrate the basic 8-electron model. As chemists move to heavier elements, the rules become more nuanced, but the shell structure remains central to understanding atomic behavior.
Key Facts
YouTube Angle
Suggested video title for this topic:
"Why does the periodic table stop being simple after neon?"
Was this answer helpful?
Tap a reaction — it helps us pick what to cover next.