In this page we will explore electron configuration, orbitals, and quantum numbers.
Electron Configuration
The chemistry department at UC Davis has an excellent page describing electron configuration, quantum numbers and describes in detail each of the principles, its worth a look, click the image to link to their site.
Principles Describing Electron Configuration
There are three principles (or rules) that describe electron configuration:
Pauli Exclusion Principle
Aufbau Principle
Hund's Rule
Once you understand how these principles work you will be able to configure electrons easily. The short video below demonstrates how each rule applies to electron configuration.
Quantum Numbers and Atomic Orbitals
Professor Dave does a nice job describing the quantum numbers and giving an example of how to configure electrons in this video.
Diagonal Rule
The diagonal rule is a great way to remember the order that electron orbitals get filled.
Click the image to link to a website describing how this rule is used.
Orbitals
Because electrons will fill according the diagonal rule, it gives meaning to the shape of the periodic table. The following image highlights each orbital region on the periodic table:
Remember that in the quantum model of the atom, we have thrown out Bohr's circular orbits and replaced them with 3-dimensional clouds of probability--also known as "orbitals". Below are images corresponding to each shape of the orbitals.