Which statement best defines kinetic molecular theory?

The correct choice provides an accurate and comprehensive description of kinetic molecular theory, which is fundamental in understanding the behavior of gases. According to this theory, gas particles are indeed in constant random motion, which accounts for the various properties of gases, such as pressure and temperature. The assertion that these particles occupy no volume reflects the idea that, at the molecular level, gas particles are much smaller than the distances between them, allowing us to approximate the volume they occupy as negligible. Additionally, stating that there are no intermolecular forces among the gas particles is crucial because it highlights that gas behavior is primarily influenced by collisions between particles rather than attractions or repulsions, which are significant in liquids and solids.

This option encapsulates the key points of kinetic molecular theory, making it distinctly accurate compared to others. Other options, by contrast, either misrepresent the theory's focus or incorrectly imply the presence of intermolecular forces, which fundamentally alters the understanding of gas behavior.