Final answer:
A nonpolar molecule only exhibits London dispersion forces as its intermolecular force, which occurs due to temporary fluctuations in the electron distribution around atoms.
Step-by-step explanation:
The only intermolecular force that a nonpolar molecule can have is the London dispersion force. These forces occur in all molecules, including nonpolar ones, due to temporary fluctuations in the electron cloud surrounding atoms. These fluctuations result in a momentary imbalance in the electron distribution, creating an instantaneous dipole, which induces a dipole in neighboring molecules, leading to an attraction known as London dispersion forces.
Larger atoms are typically more polarizable than smaller ones, making their London dispersion forces relatively more significant. However, when comparing intermolecular forces, hydrogen bonding and dipole-dipole interactions are generally stronger than London dispersion forces in molecules that can exhibit them.