Concept:Molecular orbital theory determines bond order and magnetic character. Bond order = (bonding electrons − antibonding electrons)/2. Unpaired electrons make a species paramagnetic.
Explanation:For
O2: MO configuration gives bond order 2 (two unpaired electrons).
O2+ loses one π* electron → bond order = (10−5)/2 = 2.5, one unpaired electron → paramagnetic.
O2− gains one π* electron → bond order = (10−7)/2 = 1.5, one unpaired → paramagnetic.
For
N2: MO configuration gives bond order 3, diamagnetic.
N2+ loses one σ2p electron → bond order = (9−4)/2 = 2.5, one unpaired → paramagnetic.
N2− gains one π* electron → bond order = (10−5)/2 = 2.5, one unpaired → paramagnetic.
N22− gains two π* electrons → bond order = (10−6)/2 = 2, two unpaired → paramagnetic.
Now check each option:
A.
O2− (1.5, paramagnetic),
N2+ (2.5, paramagnetic) — bond orders differ.
B.
O2+ (2.5, paramagnetic),
N22− (2, paramagnetic) — bond orders differ.
C.
O2− (1.5, paramagnetic),
N2− (2.5, paramagnetic) — bond orders differ.
D.
O2+ (2.5, paramagnetic),
N2− (2.5, paramagnetic) — both bond order 2.5 and paramagnetic.
Answer:D.
O2+,
N2−