chemical questions............

1. metals
metal forms the metallic bond which the atoms are in the electron sea. The electrons in the electron sea are the free electrons. when apply the voltage difference between the metal, the electrons can easily comes out so that metal is conduct electricity.

2. non-metals
most of the non metals are form a structure as giant covalent structure or simple mollecular structure. the electrons are bond in the bond pair. the electrons are not free at all to conduct electricity.

3. semi-metals
semi metals are metal and non metals form covalent bonds. but you can see that most of the semi metal are bond by the group 3 element and group 4 element. the electrons may unbalence in some of the covalent bond as one side of the nuclear had a higher electroneagativity. so some of the electron may comes out and conduct electritcity. however the quantity of the free electrons are not as much as metal. the ability of conductivity of semi metal is smaller.