Here's why:

* Location on the Periodic Table: Sulfur is located in Group 16 (also known as the chalcogens) of the periodic table, which primarily contains nonmetals.

* Physical Properties: Sulfur is a brittle solid at room temperature, a poor conductor of heat and electricity, and lacks the characteristic metallic luster.

* Chemical Properties: Sulfur readily forms covalent bonds with other nonmetals, a key property of nonmetals.

Let me know if you have any other questions!