Bond length and bond energy | AP Chemistry | Khan Academy | Summary and Q&A

TL;DR

Diatomic hydrogen molecules form when two hydrogen atoms bond together by sharing their valence electrons, creating a stable molecule with a distance of approximately 74 picometers between the atoms.

Key Insights

• 🫀 Diatomic hydrogen molecules form through the sharing of valence electrons between two hydrogen atoms.
• 🫀 The distance between the hydrogen atoms in a diatomic hydrogen molecule is approximately 74 picometers.
• 🫀 Pulling the atoms apart or squeezing them together increases the potential energy due to various factors, including Coulomb forces and electron-electron repulsion.
• 😥 The stable point in the potential energy graph represents the minimum potential energy for diatomic hydrogen.
• 🫀 The bond energy of diatomic hydrogen, which is the energy required to separate the atoms completely, is 432 kilojoules per mole.
• ✋ Smaller atoms and higher order bonds have higher bond energies.

Transcript

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Questions & Answers

Q: How do hydrogen atoms bond together to form a diatomic hydrogen molecule?

Hydrogen atoms form a covalent bond by sharing their valence electrons, allowing both atoms to have a complete outer shell and creating a stable diatomic hydrogen molecule.

Q: What is the distance between the hydrogen atoms in a diatomic hydrogen molecule?

The distance between the centers of the hydrogen atoms in a diatomic hydrogen molecule is approximately 74 picometers.

Q: What happens to the potential energy when diatomic hydrogen molecules are pulled apart or squeezed together?

Pulling the atoms apart or squeezing them together increases potential energy. Pulling the atoms apart requires energy to overcome the Coulomb forces and increases the potential energy. Squeezing them together also increases potential energy due to repulsion between positive charges of the nuclei and overlapping of electrons.

Q: What is bond energy?

Bond energy refers to the energy required to completely separate the atoms in a bonded molecule. For diatomic hydrogen, the bond energy is 432 kilojoules per mole.

Summary & Key Takeaways

• Diatomic hydrogen, or H2, consists of two hydrogen atoms bonded together through the sharing of valence electrons.

• The distance between the centers of the hydrogen atoms in a diatomic hydrogen molecule is approximately 74 picometers.

• Pulling the atoms apart increases potential energy, while squeezing them together also increases potential energy due to the repulsion between positive charges and overlapping of electrons.