Insulators:

Insulators, or nonconductors, are materials along with electrons which are strongly bound to their atoms and need huge amounts of energy to free them from the influence of the nucleus.  An atom of good insulators have their valence shells filled along with eight electrons that mean they are more than half filled.  Any energy applied to like an atom will be distributed between an associatively huge numbers of electrons.  Instances of insulators are rubber, glass, plastics, and dry wood.