Molecular orbital theory antibonding

At first sight, the molecular orbital description of N2 looks quite different from the Lewis description ( N=N ). However, it is, in fact, very closely related. We can see their similarity by defining the bond order (b) in molecular orbital theory as the net number of bonds, allowing for the cancellation of bonds by antibonds ... 

According to molecular orbital theory the valence p-orbitals of the oxygen atoms combine to form three bonding and three antibonding orbitals in molecular oxygen, as shown in Fig. 1. 

I. Molecules containing one to four electrons. We have already seen the H2 molecule in which there are two electrons in the ou orbital. Two bonding electrons constitute a chemical bond The molecular orbital theory does not restrict itself to even numbers of bonding electrons, and so the bond order is given as one-half the difference between the number of bonding electrons and the number of antibonding electrons ... 

Molecular orbital theory predicts that overlapping six atomic p orbitals will lead to the generation of six n molecular orbitals. Three of these n molecular orbitals will be bonding orbitals, while the other three will be antibonding orbitals, as shown in Figure 1-2. 

Earlier in this chapter, you learned the definition of bond order in the valence bond theory. In molecular orbital theory, the bond order is defined as one-half the difference between the number of electrons in bonding orbitals and the number of electrons in antibonding orbitals. Mathematically, this can be expressed as... 

Molecular orbital theory is an alternative approach to bonding than valence bond theory. According to this theory, molecular orbitals form when orbitals overlap. This overlap gives rise to bonding orbitals and antibonding orbitals. 

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