2nd Period Homonuclear molecules Molecules Electron configuration Bond order Bond length Bond energy (pm) (kJmol-1) KK o2s)2 108 Be2KK(a2)2(2)2 0 245 B2 KK(o2s)2(o2s )2(T2p) 2 159 289 C2KK(a2)2(2)2(T2) 124 599 KK(o2)2(23)2(兀2p)4(a2p)2 110 942 O2KK(o2)2(o2)2(a2p)2(m2y)4(x2p 121 F2KK(a2y2(o23)2(2)2(mp)(2p 141 154 6
2nd Period Homonuclear Molecules 6 Molecules Electron configuration Bond order Bond length Bond energy （pm) (kJ⋅mol-1) Li2 KK（σ2s)2 1 267 108 Be2 KK（σ2s)2 （σ2s *)2 0 245 9 B2 KK （σ2s)2 （σ2s *)2（π2p)2 1 159 289 C2 KK （σ2s)2 （σ2s *)2（π2p)4 2 124 599 N2 KK （σ2s)2 （σ2s *)2（π2p)4（ σ 2p)2 3 110 942 O2 KK （σ2s)2 （σ2s *)2（ σ 2p)2（π2p)4 (π2p *)2 2 121 494 F2 KK （σ2s)2 （σ2s *)2（ σ 2p)2（π2p)4 (π2p *)4 1 141 154
MO Energy 十忡十件料世封 2 L: B Energy crossing between O2p and T2n MOs Q: Among the molecules above, (1)Which one is the most stable?(2)Which ones have paramagnetism? 7
MO Energy Q: Among the molecules above, (1) Which one is the most stable? (2) Which ones have paramagnetism? 7 Energy crossing between σ2p and π2p MOs
Heteronuclear diatomic molecules 丌 p 02 P 丌 p co(ground state): 2 s KK(25)2(a25)2(2n)4(o2p)2 U s Is C Co 8
Heteronuclear Diatomic Molecules 8 CO (ground state): KK（σ2s)2 （σ2s * )2 （π2p)4（σ 2p)2
Heteronuclear diatomic molecules No (ground state): s 2s KK(2)3(2)2(a2p)2(2)2(m2p) Is Is NO
Heteronuclear Diatomic Molecules 9 NO (ground state): KK (σ2s)2(σ2s *)2 (σ 2p)2 (π2p)4 (π2p *)1 N NO O
Heteronuclear diatomic molecules 补书 LiF (ground state) (1s1)2(1s)2(2sp)2(o)2(m)4 Li LIF F
Heteronuclear Diatomic Molecules 10 LiF (ground state): (1sLi)2 (1sF)2 (2sF)2 (σ )2 (πnb)4