Mixed Groups

Properties of Metalloids Some elements called metalloids share characteristics of both metals and nonmetals. Metalloids can form ionic and covalent bonds with other elements can have metallic properties.

Some metalloids can conduct electricity better than most nonmetals, but not as well as some metals, giving them the name: semiconductors. The metalloids are mixed up group of elements from Groups 13-17

The Boron Group Boron, a metalloid, is the first element in Group 13. (3 Valence electrons) Aluminum, a metal in Group 13, is the most abundant metal in Earth’s crust. It is used in soft-drink cans, foil wrap, cooking pans, and as siding. It is also used in the production of airplanes.

The Carbon Group The carbon family has 4 Valence electrons. Carbon is a nonmetal Silicon and germanium are metalloids Tin and lead are metals

More on Carbon All organic compounds contain carbon (humans and plants), but not all carbon compounds are organic.

Allotropes Allotropes (test question) which are different forms of the same element, have different molecular structure. One allotrope of silicon is hard, gray substance, and the other is a brown powder. Silicon is the main component in semiconductors, or elements that conduct an electric current under certain conditions.

IPOD Many electronics that you use every day, like the computer need semiconductors to run. IPOD anyone?

Allotropes of Carbon What does your graphite pencil and a diamond have in common? They are both made of carbon.

Nitrogen Group The nitrogen family makes up Group 15. (5 Valence Electrons) These elements tend to share electrons and to form covalent compounds with other elements. Nitrogen is used to make fertilizers.

Diatomic Molecules Every breath you take, you breathe in 80% nitrogen in the form of a diatomic molecules N2 The bad thing is that you and other animals and plants can’t use nitrogen in its diatomic form.

The Oxygen Group Group 16 (6 Valence electrons) Makes up 21% of the air. Oxygen exists in the air as a diatomic molecule O2

Synthetic Elements Synthetic – is made in a laboratory, i.e., not found naturally in the Earth. Each synthetic element has more than 92 protons. They also are radioactive

Bombarding plutonium with protons will change it to americium, element 95. This element is used in home smoke detectors, a small amount of americium emits harmless, charged particles.

An electric plate in the smoke detector attracts some of these charged particles. When a lot of smoke is in the air, it interferes with the electric current, which immediately sets off the alarm in the smoke detector.