Here's why:
* Solids: In a solid, the particles are closely packed and held together by strong intermolecular forces. These forces keep the particles in a fixed, rigid structure.
* Liquids: In a liquid, the particles have more freedom of movement. While still attracted to each other, the intermolecular forces are weaker, allowing the particles to slide past one another.
To melt a solid, you need to provide enough energy (usually in the form of heat) to overcome the intermolecular forces holding the particles in a rigid structure. This allows them to move more freely and transition to the liquid state.
The strength of the intermolecular forces determines the melting point of a substance. Substances with strong intermolecular forces have higher melting points because it takes more energy to overcome them.
