Hydrogen can bond to itself. Hydrogen makes positive ions. Hydrogen is a gas at room temperature. Hydrogen is combustible.
I gave my students this multiple choice question: Hydrogen is located on the left side of the periodic table in the same column as the alkali metals, but it has characteristics of a nonmetal. Which of the following is a physical property of hydrogen?

Only one answer is correct among these 4 choices:
- Hydrogen can bond to itself.
- Hydrogen makes positive ions.
- Hydrogen is a gas at room temperature.
- Hydrogen is combustible.

Could you tell me which one is correct?

Hydrogen is a gas at room temperature.