The Central Themes of MO Theory

Several key ideas of MO theory appear in its description of the hydrogen molecule and other simple species. These ideas include the formation of MOs, their energy and shape, and how they fill with electrons. 

Formation of Molecular Orbitals Because electron motion is so complex, we use approximations to solve the Schrodinger equation (see Section 7.4) for an atom with more than one electron. Similar complications arise even with H2, the simplest molecule, so we use approximations to solve for the properties of MOs. The most common approximation mathematically combines (adds or subtracts) the atomic orbitals (atomic wave functions) of nearby atoms to form MOs (molecular wave functions). 

When two H nuclei lie near each other, as in H2, their AOs overlap. The two ways of combining the AOs are as follows  

The two possible combinations for hydrogen atoms and Hr are AO of Ha + AO of Hb = bonding MO of H2 (more e density between nuclei) 

Notice that the number of AOs combined always equals the number of MOs formed two H atomic orbitals combine to form two H2 molecular orbitals. 

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The Central Themes of MO Theory 338 Homonuclear Diatomic Molecules of Period 2 Elements 341 CHAPTER REVIEW GUIDE 345 PROBLEMS 346... 

Molecular Orbital (MO) Theory and Electron Delocalization Central Themes of MO Theory Homonuclear Diatomic Molecules of the Period 2 Elements... 

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