Here's why:

* Xenon is a noble gas. Noble gases are monatomic, meaning they exist as individual atoms rather than molecules.

* London dispersion forces are present in all substances. These forces arise from temporary fluctuations in electron distribution around atoms or molecules, creating temporary dipoles. These temporary dipoles can induce dipoles in neighboring atoms or molecules, leading to weak attractions.

While xenon is a relatively large atom with many electrons, the London dispersion forces between two xenon atoms are still very weak due to the lack of permanent dipoles and the absence of other intermolecular forces like hydrogen bonding or dipole-dipole interactions.