When a liquid becomes a gas, what happens to the molecules?

When a liquid transitions to a gas, a process known as vaporization, the molecules gain energy, typically from heat, causing them to move farther apart. This occurs because the increased energy overcomes the intermolecular forces that hold the molecules closely together in the liquid state. As a result, the molecules begin to spread out and transition into a gaseous state, where they can move freely and are not constrained by the close proximity that exists in the liquid form. Therefore, the correct choice illustrates that during this transformation, the increased molecular movement leads to a greater distance between them, which characterizes the gaseous state.