Higher the bond order, more is the stability. The bond order of the given species can be calculated as MO configuration of C2=(6+6=12)
=σ1s2,σ*1s2,σ2s2,σ*2s2,π2px2≈π2py2 BO=‌
Nb−Na
2
=‌
8−4
2
=‌
4
2
=2
MO configuration of Li2=(3+3=6) =σ1s2,σ*1s2,σ2s2 BO=‌
4−2
2
=1 MO configuration of O2(8+8−1=15)
=σ1s2,σ*1s2,σ2s2,σ*2s2,σ2pz2,π2px2
≈π2py2,
*
Ï€
2px1 BO=‌
10−5
2
=2.5 MO configuration of He2=(2+2−1=3) =σ1s2,σ*1s1 BO=‌
2−1
2
=‌
1
2
=0.5 Thus, the order of bond orders of the given species is He2+<Li2<C2<O2+ Since, bond order α stability. Thus, order of stability will also be the same.