Bond Order:
Bond order is defined as half the difference between the number of electrons present in bonding molecular orbitals and antibonding molecular orbitals.
Mathematically,
Bond order = (Number of bonding electrons − Number of antibonding electrons) / 2
Calculation of bond order:
(i) N2
Electronic configuration (MO):
(σ2s)2(σ*2s)2(π2px)2(π2py)2(σ2pz)2
Bonding electrons = 10
Antibonding electrons = 4
Bond order = (10 − 4) / 2 = 3
(ii) O2
Electronic configuration (MO):
(σ2s)2(σ*2s)2(σ2pz)2 (π2px)2(π2py)2 (π*2px)1(π*2py)1
Bonding electrons = 10
Antibonding electrons = 6
Bond order = (10 − 6) / 2 = 2
(iii) O2+
O2+ is formed by removal of one electron from O2.
Bonding electrons = 10
Antibonding electrons = 5
Bond order = (10 − 5) / 2 = 2.5
(iv) O2−
O2− is formed by addition of one electron to O2.
Bonding electrons = 10
Antibonding electrons = 7
Bond order = (10 − 7) / 2 = 1.5
Final Summary:
| Species | Bond Order |
|---|---|
| N2 | 3 |
| O2 | 2 |
| O2+ | 2.5 |
| O2− | 1.5 |
\(O - O\) bond length in \(H _2 O _2\) is X than the \(O - O\) bond length in \(F _2 O _2\)The \(O - H\) bond length in \(H _2 O _2\)is Y than that of the\(O - F\) bond in \(F _2 O _2\)Choose the correct option for \(\underline{X} and \underline{Y}\) from those given below :
The correct order of bond enthalpy \(\left( kJ mol ^{-1}\right)\) is :