Question

Why are non metals gaseous at room temperature?

Answer 1

 It is a consequence of their electronic structure, which is mostly filled. In their elemental states they tend to form either monatomic molecules, such as the inert gases, or they form diatomic molecules, like nitrogen, oxygen, chlorine, fluorine, etc. These structure lend themselves to isolated, electronically complete molecules that do not bond with other molecules and are therefore more likely to form gases than liquids or solids.

Answer 2

The reason why non-metals are gaseous at room temperature is because of their mostly filled electronic structure. In their molecular form, non-metals exist as monoatomic molecules such as the inert gases (or) diatomic molecules like H₂, Cl₂, O₂, etc.. Their atoms are covalently bonded in a molecule, while the intermolecular forces of attraction are weak that can be easily overcome at room temperature. Therefore, they exist as gases at room temperature.