Worked example: Interpreting potential energy curves of diatomic molecules | Khan Academy

TL;DR

This video explains how to determine the potential energy as a function of internuclear distance for different diatomic molecules based on their bond order and atomic radii.

Transcript

• [Instructor] In a previous video, we began to think about potential energy as a function of internuclear distance for diatomic molecules. What do I mean by diatomic molecules? Well, we looked at molecular hydrogen, or H2, which is just two hydrogens covalently bonded to each other. And at standard temperature and pressure, there, they would natur... Read More

Key Insights

• 🫀 Potential energy for diatomic molecules is influenced by bond order and atomic radii.
• ✋ Higher bond order results in shorter internuclear distance and higher bond energy.
• 🫀 Smaller atoms have shorter stable internuclear distances.
• ✋ The graph with the highest bond energy corresponds to the diatomic molecule with the highest bond order.
• 🫀 Atomic radii change based on the number of electrons and position in the periodic table.
• 🫀 Comparing bond order takes precedence over atomic radii when determining diatomic molecules.
• 😘 Internuclear distance at the lowest potential energy is a function of both atomic radii and bond order.

Questions & Answers

Q: How does bond order affect the potential energy of diatomic molecules?

Bond order, such as a single, double, or triple bond, affects the potential energy by influencing the internuclear distance and bond energy. Higher bond order leads to shorter internuclear distance and higher bond energy.

Q: How do atomic radii contribute to the potential energy of diatomic molecules?

Atomic radii play a role in determining the internuclear distance with the lowest potential energy. Smaller atoms have shorter stable internuclear distances, resulting in lower potential energy.

Q: How can we determine the diatomic molecule based on potential energy graphs?

By analyzing the bond energy and considering the bond order, we can identify diatomic molecules. The graph with the highest bond energy corresponds to the diatomic molecule with the highest bond order.

Q: What factors should be considered when determining the diatomic molecule based on potential energy?

Bond order and atomic radii are crucial factors. Bond order determines the bond energy and internuclear distance, while atomic radii affect the stability and shortest distance between the nuclei.

Summary & Key Takeaways

• The video explores the potential energy as a function of internuclear distance for diatomic molecules such as hydrogen, nitrogen, and oxygen.

• The distance between diatomic molecules' nuclei with the lowest potential energy is determined by their atomic radii and bond order.

• Bond order, determined by the number of covalent bonds between atoms, influences the internuclear distance and bond energy.