Aufbau principle

Definition

The Aufbau principle is a guideline used in organic chemistry to determine the electron configuration of an atom, molecule, or ion. It states that electrons occupy the lowest energy orbitals first before filling higher energy levels.

Related terms

Electron Configuration:

The arrangement of electrons in an atom's or molecule’s orbitals.

Orbital:

A region around an atom's nucleus that can hold up to two electrons, with opposite spins.

Pauli Exclusion Principle:

A principle stating that no two electrons in an atom can have identical quantum numbers, ensuring each electron has a unique state