Final answer:
Nonmetals are often found as gases at room temperature and include elements such as nitrogen, oxygen, and the noble gases. They differ significantly from metals, which are usually solids, except mercury which is a liquid at room temperature.
Step-by-step explanation:
The substance you would mostly find in gaseous form at room temperature is likely a nonmetal. Nonmetals exhibit various properties and states of matter at room temperature and pressure. Many nonmetals are gases, like nitrogen (N₂) and oxygen (O₂), while some are solid, such as sulfur, and only one, bromine (Br₂), is a liquid under normal conditions. Unlike metals, which are typically solid at room temperature with the exception of mercury (Hg), the nonmetal gases often exist as diatomic molecules. In addition, noble gases such as helium (He) and neon (Ne) are monatomic nonmetal gases.