why are covalent compounds poor conductors of electricity?
The electrons in the outermost shell of the covalent compounds are shared by the nearby atoms. As there are no free electrons (only at absolute zero) for conducting electricity, the covalent compounds are perfect insulators at absolute zero. As the temperature increases, some electrons move from valence band to conduction band. This gives rise to the conductivity. But, as the number of charge carriers are very low, covalent compounds are poor conductors.
It is because while making covalent bonds, they use the electrons of the carbons and thus there may not the fulfillment of carbon electrons to conduct electricity.... but also some of them do not conduct electricity like Diamond. Their conduction depentds upon the number of covalent bonds. jst for examples: In diamond, the co-valent chain is formed using all the 4 electron and thus due to the lack of free electron it is unable to conduct electricity ,,, whereas in the case of other like graphite only 3 electrons are used up while forming covalent bond... and because now 1 electrons is remaining , it can conduct electricity easily....Thank you best wishes