Section 3 Ionic Bonds Mr Gardner 7 th

Section 3: Ionic Bonds Mr. Gardner 7 th Srade Science

Key Concepts • What are ions, and how do they form bonds? • How are the formulas and names of ionic compounds written? • What are the properties of ionic compounds?

Key Terms • • • Ionic Polyatomic Ionic compounds Chemical formula Subscript Crystal

Ions and Ionic Bonds • Almost every atom feels better when they have 8 electrons in their valence shell. • Ions: A group of atoms that have an electric charge. • Either positive or negative • When an atom looses an electron it becomes positive • When an atom gains an atom • Polyatomic Ions • Ions made of more than one atom.

Ionic Bonds

Chemical Formulas and Names • Chemical Formula: A combination of symbols that shows the ration of elements in a compound.

Formulas of Ionic Compounds • When ionic compounds form, the ions come together in a way that balances out the charges on the ions. The chemical formula for the compounds reflects this balance. • Subscript: tells you the ration of elements in the compound.

Naming Ionic compounds • The name of the positive ion comes first, followed by the name of the negative ion (usually). • Na. Cl = Sodium Chloride • Mg. Cl 2 = Magnesium Chloride • Usually ends in ide • Polyatomic ions are different: • Usually ends in ate • NH 4 NO 3 = Ammonium Nitrate

Properties of Ionic Compounds • Ionic Crystals • Ions form an orderly, three dimensional arrangement called Crystals. • High Melting points • Electrical Conductivity