Question

Which of the following has the highest O-O bond energy?
A.\[{O_2}\]
B.${O_2}^{2 + }$
C.${O_2}^ - $
D.${O_2}^{2 - }$

Answer 1

Hint:The measure of the bond strength is known as the bond energy. The energy is to be given to the system in order to convert the one mole of any molecule into the constituent atoms. It is the measure of the gained stability when the atoms are bonded to each other.

Complete step by step answer:
The measure of the bond energy is measured by the heat required for the conversion for one mole of the atoms; the average of the energy is usually measured through this. The stronger is the bond when the bond energy is the highest and the distance between the atoms in that bond is the smallest.
Bond order is the number of the chemical bonds indicated by the chemical bonds between the pair of atoms and the stability is depicted by the bond order.
For the molecules showing the resonance, the bond order may not be an integer. The pi electrons involved in the delocalisation of the charge on the molecules resulting in the resonance in the molecule are the criteria essentially directing the molecule’s bond order not exactly equal to the integer.
The bond order is calculated by the difference between the electrons in the bonding and the anti- bonding orbitals.
Bond Order= Number of bonding electrons- Number of antibonding electrons/2

Higher the bond order higher will be the bond energy.
That is: Bond Order is directly proportional to Bond Energy
 The bond order is given below for different species as:
${O_2} = \frac{{8 - 4}}{2} = 2$
${O_2}^{2 + } = \frac{{8 - 2}}{2} = 3$
${O_2}^ - = \frac{{8 - 5}}{2} = 1.5$
${O_2}^{2 - } = \frac{{8 - 6}}{2} = 1$
Since the ${O_2}^{2 + }$ has the highest bond order thus the bond energy is the highest.


Note:
Bond order is usually equal to the number of bonds in between the two atoms, when the electrons are in the bonding orbital although the exceptions occur when the molecule also contains the anti- bonding orbitals. Thus it is an important parameter in the finding the stability and strength of the bond between the two molecules.