Which of the following hypothetical electronic configurations of a carbon atom () violate Hund's Rul — Atomic Structure Chemistry Question

💡 Solution & Explanation

Hund's rule requires degenerate orbitals to be singly occupied with parallel spins before pairing begins. Pauli's principle restricts an orbital to a maximum of two electrons with opposite spins. $1s^2 2s^2 2p_x^2 2p_y^0 2p_z^0$ pairs electrons in $2p_x$ before occupying $2p_y$, violating Hund's rule, but has max 2 electrons per orbital, obeying Pauli. Option C (for N) also incorrectly pairs electrons prematurely. Option B is the correct ground state for C. Option D violates Pauli.