AP Chemistry
Notation Summary
1. Orbital Filling Notation

Individual orbitals often represented by open squares or circles. For simplicity, we will represent orbitals as
only the bottom portion of the box (a line).

All electrons are represented by arrows.
Nitrogen:
_____
1s
_____
2s
_____
2px
_____
2py
_____
2pz
_____
_____
2p
_____
or
Nitrogen:
_____
1s
_____
2s
2. Electron Configuration Notation

Orbitals are written with the energy level first, then the name of the sublevel, then a superscript showing the
number of electrons in the orbital. All electrons are represented.
Nitrogen: 1s22s22px12py12pz1
Or
Nitrogen: 1s22s22p3 (Usually preferred)
3. Lewis Electron Dot Notation



Only electrons in the outermost energy level (valence) are represented.
Each electron is shown as a dot around the symbol of the element.
If electrons are together in an orbital, they will be written together in the dot notation.
Nitrogen:
N