Well, let me think. Element X does not conduct electricity well, so it must be more stable, with a strong grip on it's outer shells. If I remember correctly, that would put it closer to the right side. It breaks when hit with a hammer meaning that it's not a gas, for one, and also that it does not form strong bonds with itself. In my mind that places it near the bottom right of the periodic table, right next to the noble gasses. My guess goes to it being a metalloid, probably Tellurium.
As far a Z goes, it could be a wide range of things, if we only know that it is a good conductor. I'm going to guess it's in the range of "transition elements"
Almost all metals are good conductors of heat and electricity but alkali metals such as silver are very good conductor of heat and electricity.
Any element that is a metal.
Nonmetals
This is a metal.
Carbon nanotubes or graphene
Silver is the best conductor of electricity, and as it is costly, copper is widely used.
This element is a metalloid.
silver
graphite
Silicon or Germanium Graphite is an excellent electrical conductor
Conductor of electricity are compounds that allow electricity to pass through. They are metallic and sometimes ductile and malleable. Very common is iron. The most metallic element is francium.
Almost all metals are good conductors of heat and electricity but alkali metals such as silver are very good conductor of heat and electricity.
ice
The best conductor for heat and electricity is any type of metal element.
Any element that is a metal.
Carbon?
Carbon