Here's why:

* Electron Configuration: Xenon's electron configuration is [Kr] 4d¹⁰ 5s² 5p⁶.

* Valence Shell: The outermost shell, which is the 5th shell in this case, contains the valence electrons.

* Valence Electrons: The 5s and 5p orbitals, which are part of the outermost shell, hold a total of 8 electrons (2 + 6 = 8).

Therefore, xenon has 8 valence electrons.