As with hydrogen-like atoms, the same quantum numbers describe states that may be filled by electrons in a more complex atom:
The Pauli Exclusion Principle requires that
no two electrons may have the same quantum numbers
Here are a few atoms, showing which states are filled with electrons:
Some of this same information can also be stated with another notation.
The principle quantum number n is explicitly stated as 1, 2, 3, 4, . . .
The orbital quantum number l is given by a letter
l = 0 is an s-state
l = 1 is a p-state
l = 2 is a d-state
l = 3 is an f-state
The number of electrons in a particular "orbital" is shown by an exponent.
(c) Doug Davis, 1997; all rights reserved