Here's why:

* Location on the Periodic Table: Helium is located in Group 18 (VIIIa), which consists of noble gases. Noble gases are all nonmetals.

* Physical Properties: Helium is a gas at room temperature, and gases are generally nonmetals. It is also very unreactive, another characteristic of nonmetals.

* Electronegativity: Helium has a very high electronegativity, which is a property of nonmetals.

* Conductivity: Helium does not conduct electricity or heat well, which is another characteristic of nonmetals.

Let me know if you have any other questions!