# What is the maximum number of electrons in each orbital?

Jan 10, 2017

Two

#### Explanation:

The maximum number of electrons in any orbital is two, regardless of the nature of the orbital. This is because every electron in an atom must be unique - different in some respect from any of the others.

The differences can only come in the way of the four quantum numbers required to specify an electron:

The principle quantum number, $n$ determines the energy of the orbital and the electrons within it. (Determines the shell)

The azimuthal quantum number, $l$ determines the shape of the orbital. (Determines the subshell -$s , p , d \mathmr{and} f$)

The magnetic quantum number, ${m}_{l}$ gives the orientation of the orbital in space (${p}_{x} , {p}_{y} \mathmr{and} {p}_{z}$ for example)

By this point, the orbital in question has been uniquely characterized.

This leaves the spin quantum number, $s$ as the fourth and final difference that can exist. Because it can have only two values, (up or down), the orbital has only two possible states for the electron.

Thus, each orbital holds up to two electrons at most.