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 Electrons and Sublevels

Principal energy levels are broken down into sublevels. Theoretically there are an infinite number principal energy levels and sublevels. If you are just starting to study chemistry, you should only be concerned with the first 4 sublevels.

Each sublevel is assigned a letter.  The four you need to know are s (sharp), p (principle), d (diffuse), and f (fine or fundamental). So, s,p,d & f.

The Principal Energy Level (the #) only holds that # of sublevels.

 Principal Energy Level # of Sublevels sublevels 1 1 1s 2 2 2s  2p 3 3 3s 3p 3d 4 4 4s 4p 4d 4f 5 5 5s 5p 5d 5f 5g

Yes, the 5th energy level  holds 5 sublevels and that last one would be 5g.

The number of electrons in each sublevel

 sublevel # of electrons in each sublevel s 2 p 6 d 10 f 14 g 18

Electrons fill in energy order (Aufbau Principle) not energy level order.

NOTE-Some Principal Energy Levels start to fill before previous ones finish.

ex 4s fills before 3d, because 4s has less energy than 3d. It must fill first.

Electrons fill the sublevels in  energy order   1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

If we add the number of electrons that each sublevel holds it looks like this:

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d10 7p6

The diagram below really shows the overlap of the Principal Energy Levels

on to Sublevels and the Periodic Table