Question

How do compare bond energy of o2, o2-

• A. The bond energy of $O_2$ is greater than the bond energy of $O_2^-$.
• B. The bond energy of $O_2^-$ is greater than the bond energy of $O_2$.
• C. The bond energies of $O_2$ and $O_2^-$ are equal.
• D. The bond energy of $O_2$ is half the bond energy of $O_2^-$.

Answer 1

Answer: (A)

The bond energy of $O_2$ is greater than the bond energy of $O_2^-$.

Answer 2

The bond energy of a diatomic molecule is directly proportional to its bond order. The bond order for $O_2$ is 2, and the bond order for $O_2^-$ is 1.5. Since $O_2$ has a higher bond order, it has a greater bond energy than $O_2^-$.

For $O_2$ (16 electrons), the MO configuration leads to a bond order of $\frac{10 - 6}{2} = 2$. For $O_2^-$ (17 electrons), the MO configuration leads to a bond order of $\frac{10 - 7}{2} = 1.5$. Therefore, $BO_{O_2} > BO_{O_2^-}$, which implies Bond Energy of $O_2$ > Bond Energy of $O_2^-$.