A central assumption of the Ideal Gas model is that the molecules are 'point masses'.

• This means their actual volume is negligible (treated as zero) compared to the volume of the container.
• If the finite volume of molecules is considered (as in the van der Waals equation), the gas is no longer 'ideal'.
• Other assumptions (point particles, elastic collisions, no long-range forces) are indeed parts of the ideal gas framework.