The element in the periodic table that looks like a metal, is a poor thermal conductor, and acts as an electrical semiconductor is

The answer to this question would be: Silicon(Si) 

Sillicon is a metalloid element which looked like metal but has a poor thermal conductor and acts as an electrical semiconductor. Silicon has atomic number 14 and has 4 valence electron. Silicon was the material that can be used for making many things like glass, ceramic or synthetic polymer.