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Chapter 20. Metals, Non-metals and Metalloids. Section 2--Nonmetals. Most of your body’s mass is made of oxygen, carbon, hydrogen and nitrogen Calcium makes up the remaining 4% of body mass Nonmetals —are elements that usually are gases or brittle solids at room temp.
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Chapter 20 Metals, Non-metals and Metalloids
Section 2--Nonmetals • Most of your body’s mass is made of oxygen, carbon, hydrogen and nitrogen • Calcium makes up the remaining 4% of body mass • Nonmetals—are elements that usually are gases or brittle solids at room temp. • Usually gases or brittle solids at room temp • They are not malleable or ductile • They are not good conductors
All nonmetals except hydrogen are found at the right of the stair-step line. • Noblegases—group 18—make up the only group of elements that are all nonmetals. • Most nonmetals can form ionic and covalent compounds • Hydrogen—90% of Earth’s atoms • Most hydrogen on Earth is part of water • When water breaks down into elements, hydrogen becomes diatomic
Halogens • Halogens—Group 17—are very reactive • Form compounds that have many uses—toothpaste, disinfectants, etc. • If a halogen gains an electron from a metal, an ionic compound called salt is formed • In the gaseous state, halogens form reactive diatomic covalent molecules • Halogens are ID’d by their distinctive colors
Uses of Halogens—check pg. 619 • Noble gases—noble gases exist as isolated atoms • They are stable because their outermost energy levels are full • No naturally occurring noble gas compounds are known • The stability of noble gases makes them useful • Ex: balloons, neon lights, electric lightbulbs, etc.
