alleryWhich of the following diatomic species is paramagnetic in its ground state?
AN₂
BF₂
CO₂
DCl₂
Answer & Solution
Correct answer: C. O₂
1. Paramagnetism requires unpaired electrons.
2. MO diagram of O₂ places its last two electrons in two DEGENERATE π* orbitals.
3. By Hund's rule, these are unpaired — so O₂ is paramagnetic (and blue when liquid).
4. N₂, F₂, Cl₂ have all electrons paired → diamagnetic.
_Source: syllabus Chem Ch 4 §4.7 (MO of O₂)_
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