Silicon is one example of an element that has some metallic and some non-metallic properties. Other elements with a mix of metallic and non-metallic properties include boron, germanium, arsenic, antimony and tellurium.
Elements that share metallic and non-metallic properties are termed metalloids by chemists. Silicon, a metalloid familiar to many individuals, possesses a somewhat metallic physical appearance but lacks the ability to conduct electricity as efficiently as pure metals. Due to the mixed properties of metalloids, their reactivity with other elements varies considerably. Often, the other element reacting with the metalloid determines whether the metalloid behaves more like a metal or more like a non-metal in the reaction.