There are four layers of these electrons are, s, p, d, and f.
Each one has a certain number of shells, in different shapes, that can hold two electrons.
S- Has one shell, shaped like a circle, so in total can hold 2 electrons.
P- has three shells, shaped like an infinity symbol, so in total can hold 6 electrons
D- has five shells, shaped, err, dunno how to describe it, can hold 10 electrons.
F- has 7 shells, um, even more dunno how to describe it, can hold 14 electrons
There doesn't only have to be one of each shell though. There can be two S levels, and one P level, and no D or F levels.
(search up electron configuration it'll have a chart of the order in which these come in)
Each layer will be stated as Number layer electron number.
For example, the first layer of electron level would be 1, because it's the first layer, S, because that's what the first layer is, and if it was completely filled, 2.
So, 1s2.
If you were going to add another level, which would also be a S level, but it only has one electron, you would say:
2s1,
because it's the second s level and has one electron in it.
And to put the two together, just say:
1s2, 2s1
NOTE: if you were going to add another level, it would be a P level, but it wouldn't be 3p something, it would be 1p something because it is the first electron level.
Another note: if you have three layers of electrons, or just six electrons, you would just say 1p6. (because the P orbital can hold 6 electrons)
