In gases, the particles are widely spaced and have high kinetic energy, resulting in weak attractive forces between them. This is because the intermolecular forces in gases are primarily van der Waals forces, which are weaker compared to the stronger forces present in solids and liquids. In solids, the particles are closely packed and have strong attractive forces, while in liquids, the particles are closer together than in gases, leading to stronger intermolecular forces. Therefore, the correct answer is gases.