Textbook Problem

The diatomic molecule OH exists in the gas phase. The bond length and bond energy have been measured to be 97.06 pm and 424.7 kJ/mol, respectively. Assume that the OH molecule is analogous to the HF molecule discussed in the chapter and that molecular orbitals result from the overlap of a lowerenergy p_z, orbital from oxygen with the higher-energy ls orbital of hydrogen (the O—H bond lies along the z-axis).

a. Which of the two molecular orbitals will have the greater hydrogen 1s character?

b. Can the 2p_x orbital of oxygen form molecular orbitals with the 1s orbital of hydrogen? Explain.

c. Knowing that only the 2p orbitals of oxygen will interact significantly with the 1s orbital of hydrogen, complete the molecular orbital energy-level diagram for OH. Place the correct number of electrons in the energy levels.

d. Estimate the bond order for OH.

e. Predict whether the bond order of OH⁺ will be greater than, less than, or the same as that of OH. Explain.