Question

Two elements that are gases at room temperature?

Answer 1

Two elements that, at room temperature are gases are Hydrogen (${\mathrm{H}}_2$), and Oxygen (${\mathrm{O}}_2$).

1. Hydrogen exists as ${\mathrm{H}}_2$ at room temperature. Since hydrogen has atomic number one, and to get stabilized it needs one more hydrogen so therefore it exists as ${\mathrm{H}}_2$(which is gaseous in-state).
2. Oxygen exists as ${\mathrm{O}}_2$ at room temperature. Oxygen has atomic number 8. The electronic configuration of oxygen will be (2,6). So therefore it needs two more electrons to get stabilized (octet). It shares two-electron with another oxygen and exists as ${\mathrm{O}}_2$(which is gaseous in-state) at room temperature.