# How many electrons does each shell hold? [duplicate]

why some times 2nd shell onward it can hold 8 electrons and other times it is like they can hold K2 L8 M18 N32? when do i have to use first method(K2 L8 M8 N8) and when to use second method (k2 L8 M18)? I'm really confused.

## marked as duplicate by Mithoron, paracetamol, M.A.R., Todd Minehardt, jerepierreJun 29 '17 at 16:11

• Have you learned about the subshells as well? The first shell only has $s$, the second one has $p$ and $s$, the third one has $d$ as well, and so forth. Also, you might take a look at here, if it helps. – M.A.R. Apr 7 '15 at 13:27