How can I tell how many electrons can fit in a subshell?

When figuring the electron configuration for an element, how do you know how many electrons go in each subshell(orbital)? Endie

	Vocabulary
	azimuthal quantum number () electron magnetic quantum number (m) orbital shell subshell

A subshell is a set of electrons that all have the same value of ell

(azimuthal quantum number). You can think of ell

as a label for a group of orbitals that have related shapes. A subshell with ell

=0 is called an s subshell and contains spherical orbitals; a subshell with ell

=1 is called a p subshell and contains dumbbell shaped orbitals; a subshell with ell

=2 is called a d subshell and contains (mainly) orbitals that look like 4-leafed clovers.

The number of possible orbitals in a subshell is determined by the number of possible m values for the subshell. Think of m as a label for individual orbitals within the subshell. For every m value that is allowed, there is one orbital in the subshell.

Allowed values of m are integers between - ell to + ell , including zero.

The number of possible m values determines the number of orbitals in a subshell.
	possible values of m	number of orbitals in this subshell
0	0	1
1	-1, 0, +1	3
2	-2, -1, 0, +1, +2	5
3	-3, -2, -1, 0, +1, +2, +3	7

Each orbital can hold a maximum of two electrons, so the maximum number of electrons you can put into the subshells are 2, 6, 10, and 14 for s, p, d, and f subshells, respectively.

Author: Fred Senese senese@antoine.frostburg.edu

General Chemistry Online! How can I tell how many electrons can fit in a subshell?