According to Hund's Rule, how should electrons be distributed among orbitals?

Hund's Rule states that electrons must occupy degenerate orbitals (orbitals of the same energy) singly before any pairing occurs. This means that when there are multiple orbitals available at the same energy level, each orbital gets one electron first, and only after all orbitals contain one electron will pairing begin. This distribution minimizes electron-electron repulsion and leads to a more stable arrangement within the atom.

Understanding this principle is essential because it helps explain the observed electron configurations of many elements, particularly in organizing the way elements fill their orbitals in the periodic table. The distribution according to Hund's Rule is particularly noticeable in transition metals, where electron stability and magnetic properties are influenced significantly by this rule.