Question

Why is a carbon is a metaloid ?

Answer 1

 The reason carbon is classified as a metalloid is that some organic compounds from with carbon molecules will conduct electricity. These compound usually consist of benzene rings. In these rings the carbons are unsaturated so they have double bonds. These double bonds consist of electrons that can move around the benzene ring. 
Graphite is a good example of carbon as a conductor. Graphite is sheets and sheets of these benzene molecules attached together (see the link provided). This material is used in many motors and many be referred to as a brush................

Answer 2

No it is a nonmetal as it's electronic configuration is 2,6