Chapter 19 Section 2

1. Chapter 19 Section 2 Nonmetals

2. Properties of Nonmetals • Gases or brittle solids • Not malleable, ductile, or shiny • Do not conduct heat or electricity well • All elements to the right of the stair step plus hydrogen

3. Bonding in Nonmetals • Nonmetals hold tightly to their electrons! Ionic Bonding Covalent Bonding • Nonmetals take electrons from metals and become negative • NaCl • Nonmetals share their electrons with other nonmetals • O2

4. Hydrogen • 90% of the atoms in the universe • Highly reactive! • Most found on Earth is in water • Diatomic molecule = 2 atoms of the same element in a covalent bond

5. Halogens • Group 17 • 7 valence electrons = very reactive! • Salt = a halogen atom ionically bonded to a metal • Forms diatomic molecules in gaseous state

6. Uses of Halogens • Fluorine – prevents tooth decay • Chlorine – disinfects water and used to whiten things • Salts – to eat! • Bromine (the only nonmetal that is a liquid) – dyes • Iodine – prevents goiter • Sublimates – a solid turns directly into a vapor without forming a liquid

7. Noble Gases • Exist as single atoms • Stable (outer energy levels are full) • Uses • Helium – blimps • Neon and argon – neon lights • Argon and krypton - lasers