Final answer:
Hund's Rule states that electrons fill degenerate orbitals singly with parallel spins before pairing up, minimizing electron repulsion and determining the ground state electron configuration of atoms or molecules. Orbital filling diagrams visually represent this electron arrangement.
Step-by-step explanation:
What is Hund's Rule?
Hund's Rule is a principle in chemistry that implies the most stable electron configuration in an atom is achieved when the maximum number of unpaired electrons with parallel spins are present in degenerate orbitals. In other words, electrons will occupy separate orbitals within the same sublevel before pairing up. It is important when determining the electron configuration of an atom to follow this rule to minimize the repulsion between electrons. When filling orbitals that have the same energy (degenerate), electrons are placed one at a time into these orbitals, and each electron has the same spin direction. This rule assists in predicting the ground state of an atom or molecule.
An orbital filling diagram is a visual representation used to show the placement of electrons in an atom's orbitals. According to Hund's Rule, when using an orbital filling diagram, you should add electrons to each orbital so that every orbital in a sublevel gets one electron before any of them gets a second. These diagrams use arrows pointing up or down to represent the spins of electrons.