Why are covalent compounds considered insulators?

Covalent compounds are considered insulators primarily because they do not have free-moving charged particles. In covalent compounds, atoms share electrons to achieve stable electron configurations. This electron sharing typically results in the formation of molecular structures where the electrons are localized between specific pairs of atoms. As a result, there are no free-moving ions or electrons that can carry electrical charge.

In contrast, substances that are good conductors of electricity, such as metals, have free electrons that can move throughout the material, allowing them to conduct an electric current. The absence of mobility in charged particles within covalent compounds is the key reason for their insulating properties.

The other choices provide aspects that do not directly relate to the electrical conductivity of covalent compounds. For example, the lack of covalent bonds, the physical state of being gaseous at room temperature, and being solid at room temperature are irrelevant to the mechanism of electrical conductivity in these compounds.