Section 6: Review and Discussion Questions

Why does an electron shared by two nuclei have a lower potential energy than an electron on a single atom? Why does an electron shared by two nuclei have a lower kinetic energy than an electron on a single atom? How does this sharing result in a stable molecule? How can this affect be measured experimentally?

Explain why the bond in an H2

molecule is almost twice as strong as the bond in the H+2 ion. Explain why the H2 bond is less than twice as strong as the H+2

bond.

Be2

is not a stable molecule. What information can we determine from this observation about the energies of molecular orbitals?

Less energy is required to remove an electron from an F2

molecule than to remove an electron from an F atom. Therefore, the energy of that electron is higher in the molecule than in the atom. Explain why, nevertheless, F2 is a stable molecule, i.e., the energy of an F2

molecule is less than the energy of two F atoms.

Why do the orbitals of an atom "hybridize" when forming a bond?

Calculate the bond orders of the following molecules and predict which molecule in each pair has the stronger bond:

C2

or C+2

B2

or B+2

F2

or F−2

O2

or O+2

Which of the following diatomic molecules are paramagnetic: CO, Cl2

, NO, N2

?

B2

is observed to be paramagnetic. Using this information, draw an appropriate molecular orbital energy level diagram for B2.

---