Atomic Orbital
A mathematical function describing the region around a nucleus where an electron of given energy is most likely to be found.
Formula / equation
|ψ|² = probability density
Unit
Dimensionless
In depth
Orbitals are solutions of the Schrödinger equation, labelled by three quantum numbers and each holding at most two electrons of opposite spin. Their shapes — spherical s, dumbbell p, cloverleaf d — control the directionality of covalent bonds and therefore molecular geometry.
Examples in the real world
The spherical 1s orbital of hydrogen, the three mutually perpendicular 2p orbitals, and the five 3d orbitals of transition metals.