Summary of Electron Configurations

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The number of electrons in each sublevel

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

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

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

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

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d¹⁰ 7p⁶

Maximum number of electron in an energy level (2n²)

or written like this 2-8-18-32-50

Maximum number of orbitals in an energy level (n²)

Sublevels are broken down into orbitals

an orbital holds 2 electrons

Here is an animation of how the orbitals would look as you build out from the 1s.

Pauli Exclusion Principle

When we draw electrons, we use up and down arrows. So, if an electron is paired up in a box, one arrow is up and the second must be down.

Hund’s Rule

When filling sublevels other than s, electrons are placed in individual orbitals before they are paired up.