Degenerate orbitals are atomic orbitals sharing the same energy level, typically found in p, d, and f subshells. Hund's rule governs electron filling in these orbitals, stating:
• Electrons occupy each orbital singly within a subshell before any orbital is doubly occupied.
• Electrons in singly occupied orbitals possess identical spins (either all spin-up or all spin-down).
This rule arises from electron-electron repulsion, where electrons maximize spatial separation by occupying distinct orbitals before pairing. Consequently, a system achieves the highest possible number of unpaired electrons with parallel spins.
The following concepts are unrelated to electron filling in atomic orbitals:
• Planck's Law correlates photon energy with its frequency.
• De Broglie's wave-particle duality posits that matter exhibits both wave and particle characteristics.
• The photoelectric effect involves electron ejection upon light incidence on a material.