Chapter 3, Problem 3.28P

Interpretation Introduction

Interpretation:

The number of AOs that three atoms from the second row of the periodic table would contribute in a linear molecule toward the productions of MOs is to be determined. The number of MOs that would be produced by the mixing of these valence shell AOs is to be determined.

Concept introduction:

According to Molecular Orbital Theory (MO Theory), when two atomic orbitals overlap significantly, they produce two molecular orbitals. One of these molecular orbitals is produced by overlap and mixing of two AOs that have the same phase. This MO is lower in energy than the individual AOs, and is called the bonding atomic orbital. The second MO is produced by the overlap and mixing of the AOs of opposite phases. It is higher in energy than the individual AOs and is called the antibonding MO.

In cases where the overlap produces an MO of the same energy, the resulting MO is called a non-bonding MO.

Only AOs of similar energies can interact to form MOs. In effect, this means only the AOs from the valence shells of the two atoms can form MOs. For atoms of elements from the second row, this means a total of four AOs, the lone 2s orbital, and the three 2p orbitals can form MOs.

The number of MOs formed is the same as the number of AOs that mix.