Question

How is it that carbon and silicon both have 4 valence electrons, and yet silicon's a metalloid and carbons not?

Answer 1

Both Silicon and Carbon belong to the Group 14. Silicon behaves very differently than other elements of the same group. Silicon is similar to carbon in concern of its valence electrons. Same as carbon, Silicon has 4 electrons in its outer orbital and to attain stable state, it can donate all its electrons like a metal or it can accept 4 electrons like non metals. Silicon thus exhibits metalloid properties as it can act both as a metal and also as a non metal and is able to be transformed into a semi conductor.