Concept: When electrons enter a subshell with multiple orbitals of identical energy (degenerate orbitals), they must follow a rule that minimizes electron-electron repulsion.
Formula: None required.
Solution: - Hund's Rule explicitly states that electrons must fill degenerate orbitals (like \( p_x, p_y, p_z \)) singly first, with parallel spins, before pairing up.
- This maximizes the total spin state and reduces electrostatic repulsion, leading to the most stable ground state configuration.
Why other options are incorrect: The Aufbau principle explains vertical filling across different energy shells. The Pauli exclusion principle limits each orbital to a maximum of two electrons. The "\( n+1 \)" rule is a typo for the \( n+l \) rule, which is part of Aufbau.
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