Here's why:
* Gases have very weak intermolecular forces. This means the particles are not strongly attracted to each other, allowing them to move freely and spread out to fill the available space.
* Liquids have stronger intermolecular forces than gases, but still have some freedom of movement.
* Solids have the strongest intermolecular forces, keeping the particles tightly packed together in a fixed arrangement.
Therefore, gases have the most space between their particles.
