1.2 Atomic Structure: Orbitals

Wave Function (ψ)

A mathematical expression that describes the behavior of an electron in an atom; the solution to a wave equation.

Orbital

The volume of space around a nucleus where an electron is most likely to occupy, represented by the square of the wave function (ψ 2 ).

Electron Cloud

The region around a nucleus where an electron is likely to be found, appearing as a blurry space without a sharp boundary.

s Orbital

A spherical-shaped orbital with the nucleus at its center; can hold a maximum of 2 electrons.

p Orbital

A dumbbell-shaped orbital that has two lobes; can hold a maximum of 6 electrons across three 2p orbitals.

d Orbital

A cloverleaf-shaped orbital that can hold a maximum of 10 electrons across five 3d orbitals.

Electron Shells

Layers around the nucleus that contain orbitals; each shell has a different size and energy.

First Shell

Contains one 1s orbital and holds a maximum of 2 electrons.

Second Shell

Contains one 2s orbital and three 2p orbitals, holding a total of 8 electrons.

Third Shell

Contains one 3s orbital, three 3p orbitals, and five 3d orbitals, holding a total of 18 electrons.

Node

A region of zero electron density that separates the lobes of a p orbital in space.

Electrons in Orbitals

Each orbital can be occupied by a maximum of two electrons, represented by arrows indicating their spin.