Final answer:
Silicon is classified as a metalloid because it has properties of both metals and nonmetals. It has luster like a metal, but is brittle like a nonmetal.
Step-by-step explanation:
Silicon is classified as a metalloid because it has properties of both metals and nonmetals. It has luster like a metal, but is brittle like a nonmetal. Silicon is used extensively in computer chips and other electronics because its electrical conductivity is in between that of a metal and a nonmetal.