# Electrons In Atoms

## Electron Configuration

In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. For example, the electron configuration of the neon atom is 1s2 2s22p6. http://www.wikihow.com/Write-Electron-Configurations-for-Atoms-of-Any-Element

## Orbital Notation

Orbital notation is basically just another way of expressing the electron configuration of an atom. It is very useful in determining quantum numbers as well as electron pairing.

Steps:

1) Fill in going horizontally to the right across the table. the s sublevels are first, then p, d, and then f.
2) s orbitals carry 2 electrons, p orbitals carry 6, d 10, and f 14.
3) Put the numbers in as you move along, until you reach the element you desire. Another thing is that there are a few exceptions.
Mg = [Ne] 3s2
Use the noble gas configuration for short handed notation. Long handed is just the electron config. of neon plus the valence electrons for Mg.
1s2 2s2 2p6 3s2

To check your answer, you can add the electrons together to reach the atomic number. In this case, adding 2+2+6+2 = 12, the atomic number of Mg