The Van der Waals radius is a measure of the size of an atom when it is not bonded to another atom. It represents the distance at which the attractive forces between atoms become significant, allowing them to interact without forming a chemical bond. This radius is important in understanding molecular interactions and the behavior of gases. In the context of chemistry, the Van der Waals radius helps explain how molecules like noble gases and organic compounds pack together in solids and liquids. It is typically larger than the atomic radius because it accounts for the space occupied by the electron cloud surrounding the nucleus.