Which material has the highest thermal conductivity? Which material has the highest electrical conductivity? Explain why thermal and electrical conductivity is so high with this material.

I'm a tad bit late, but here's this.

Copper has the highest thermal conductivity AND highest electrical conductivity. Why? Well, copper has a high heat tolerance(hence it building heat up faster) and has "free" electrons which contributes to being able to have a high heat AND electrical conductivity at the same time.

hope this helps, if you use this, please reword it(paraphrase)~