Question

Is oxygen a solid, liquid, or gas at room temperature?

Answer 1

Hint: Radon, xenon, krypton, argon, chlorine, neon, fluorine, oxygen, nitrogen, helium, and hydrogen are the $13$ elements that are room temperature gases. In the periodic table, most nonmetals have a gaseous elemental form.

Complete answer:
The state of a substance at room temperature is determined by its physical properties. Under typical circumstances, a substance is a gas if both its normal melting point and normal boiling point are below room temperature ( ${20}^{\circ }C$ ). The usual melting point and boiling point of oxygen are $-{218}^{\circ }C$ and $-{189}^{\circ }C$ , respectively.
Since room temperature is taken at $298K$ and is greater than oxygen's boiling point, oxygen exists as a gas at room temperature.
Because of its small size, oxygen may form a bond and hence exists as $O=O$ , that is an $O_2$ molecule. Because weak van der Waals forces of attraction hold $O_2$ molecules together, oxygen exists as a gas.

Note:
Oxygen is a chemical element with the atomic number $8$ and the symbol $O$ . It is a highly reactive nonmetal and an oxidising agent that produces oxides with most elements and other compounds. It belongs to the chalcogen group in the periodic table. By mass, oxygen is the third most abundant element in the universe, after hydrogen and helium.