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 62nd 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