KEAM 2014 Physics and Chemistry Paper

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)
MO configuration of Li2=(3+3=6)
=σ1s2,σ*1s2,σ2s2
BO=‌

4−2

2

=1
MO configuration of O2(8+8−1=15)
≈π2py2,

*

π

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.