In: Chemistry
Use molecular orbital theory to explain why the bond energy of an O2 molecule is less than that of a O2+ ion.
First calculate the total number of electrons present in the atom and draw the molecular orbital diagram.
The M O diagram for a molecule with electrons < 14 is different from that of a molecule having electrons > 14.
In the case of electrons < 14 the (pi 2px) ( pi 2py) orbitals are lower in energy than the ( sigma 2px) whereas in case of electrons > 14 its vice versa. This is because in case of electrons < 14 sp mixing takes place ( sp mixing takes place when the 2s and 2p orbitals have similar energies ) and in case of electrons > 14 the difference in energy between the s and p orbitals is greater and hence sp mixing does not take place.
Fill the electrons in the molecular orbitals following the general rules of electron filling.
Calculate the bond order using the formula, Bond order = 1/2 ( electrons in BMO - electrons in ABMO )
and the bond energy ( measure of bond strength) is directly proportional to the bond order.