Here's why:

* Location on the Periodic Table: Xenon is located in Group 18 (VIIIa) of the periodic table, which is the noble gas group. All noble gases are nonmetals.

* Physical Properties: Xenon is a colorless, odorless, and tasteless gas at room temperature. It's a poor conductor of heat and electricity, which are characteristics of nonmetals.

* Chemical Reactivity: Noble gases are known for their very low reactivity, as their outermost electron shells are full. While xenon can form compounds under extreme conditions, it is generally considered unreactive.

Therefore, based on its properties and position on the periodic table, xenon is classified as a nonmetal.