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Physical Chemistry

Atomic Orbital

Definition and meaning of Atomic Orbital in chemistry.

An atomic orbital is a mathematical function describing the probable location and behavior of an electron around an atom's nucleus. Orbitals define fuzzy regions of probability where electrons are likely to be found, with shapes determined by quantum numbers.

In more detail

Atomic orbitals arise from solving the Schrödinger equation, the fundamental equation of quantum mechanics. Unlike the classical Bohr model which proposed fixed circular electron paths, quantum orbitals are probability clouds showing where electrons are most likely to be found. Each orbital can hold up to two electrons (with opposite spins) and is characterized by four quantum numbers (n, l, m_l, m_s) that determine energy level, shape, and orientation. Different orbital types, s (spherical), p (dumbbell-shaped), d (complex, multi-lobed shapes), and f (complex), have distinct spatial arrangements that fundamentally influence chemical bonding and molecular structure.

Key facts

FieldPhysical Chemistry
Defined bySchrödinger equation
Electron capacityMaximum 2 electrons per orbital (opposite spins)
Orbital typess, p, d, f (varying shapes and complexity)
Example

The 1s orbital of hydrogen is a spherical region around the nucleus where the electron is most likely to be found; it represents the ground state of the hydrogen atom.

Frequently asked questions

How many electrons can fit in an atomic orbital?

Maximum of two electrons, and they must have opposite spins according to the Pauli exclusion principle.

What's the difference between an orbital and an electron orbit?

An orbit is a fixed path (classical model); an orbital is a probability region (quantum model) where an electron is likely to be found.

Related terms