The Aufbau principle states that, in building up an atom's electron configuration, electrons are added to the lowest-energy available orbitals first. Following this order, together with the Pauli exclusion principle and Hund's rule, reproduces the ground-state configurations of the elements. The filling order is summarised by the diagonal (Madelung) rule.

构造原理指出,在构建原子的电子排布时,电子先填入可用的最低能量轨道。遵循这一顺序,并结合泡利不相容原理和洪特规则,即可重现各元素的基态组态。其填充顺序由对角(马德隆)规则概括。