Hund's rule states that for degenerate orbitals of a subshell, electrons
A{'text': 'Pair up completely in one degenerate orbital first before spreading', 'label': 'A'}
B{'text': 'Occupy separate degenerate orbitals singly with parallel spins first', 'label': 'B'}
C{'text': 'Never occupy p or d subshells under any circumstance in an atom', 'label': 'C'}
D{'text': 'Fill only the 3d degenerate orbitals regardless of energy of others', 'label': 'D'}
Answer & Solution
Correct answer: B. {'text': 'Occupy separate degenerate orbitals singly with parallel spins first', 'label': 'B'}
1. Hund's rule of maximum multiplicity applies to degenerate orbitals.
2. Electrons occupy separate degenerate orbitals singly first with parallel spins.
3. Only after each is singly occupied do they start pairing.
4. Example: N (7 electrons) has 1s² 2s² 2p³ with three unpaired p electrons.
_Source: NCERT Class 11 Chemistry, Ch 2 "Structure of Atom", §2.6_
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