density
A material that does not conduct (or allow the 'passage' of) electricity is called an "insulator".
This is called a conductor.
Every material conducts electricity, some materials are just better than others. The best conducter of electricity is silver, but silver is very expensive. Because of this, copper is used as it is a very good conductor of electricity but it is cheap.
metal and metal and plastic
Materials that allow electricity to pass through are said to be good conductors. Conductors have free electrons allow for the flow of charged particles through the material resulting in an electric charge. Most metals are considered to be good conductors, some examples include copper, aluminum, silver, and gold.
resistance
Electricity takes the path of least resistance. Conductivity of a material has a larger impact than density does.
A material that electricity can conduct electricity.
Depends on the material. The electricity can flow through metal better then it can through wood because wood is a conductor of electricity (example).
Conductor Some materials are conductors of Heat OR Electricity. But the property is not the same for one material; example glass is a good conductor of heat but a poor conductor of electricity.
Note that "electricity" doesn't flow, only current does, which is one aspect of electricity, does. Current is the flow of electrons. A conductor. It lets heat and electrical current easily.
Electricity can pass through a wide verity of material that are conductive.
water
A material that does not conduct (or allow the 'passage' of) electricity is called an "insulator".
translucant
Insulator
copper :)