Which of the following phenomena most likely requires intermolecular forces to occur?

• A. Formation of an ionic bond between Na and Cl
• B. Absorption of light by a single molecule
• C. Radioactive decay of an atom
• D. Condensation of water vapor into liquid water

Answer: (D)

Verified step by step guidance

1. Understand the difference between intramolecular and intermolecular forces: Intramolecular forces are the forces within a molecule (such as ionic or covalent bonds), while intermolecular forces are the forces between molecules that affect how they interact with each other.
2. Analyze each phenomenon to identify whether it involves interactions between molecules or within a molecule/atom: For example, the formation of an ionic bond between Na and Cl involves intramolecular forces because it forms a bond within a compound.
3. Consider the absorption of light by a single molecule: This process involves changes within a molecule (such as electronic transitions) and does not require interactions between different molecules, so it does not primarily involve intermolecular forces.
4. Evaluate radioactive decay of an atom: This is a nuclear process occurring inside the atom and is unrelated to molecular interactions, so it does not involve intermolecular forces.
5. Recognize that condensation of water vapor into liquid water involves molecules coming together and forming intermolecular attractions (like hydrogen bonds), which is a classic example of intermolecular forces at work.