Chapter 4, Section 3 Crystal Chemistry Monday, December 14, 2009 Pages

Objectives Explain how the chemical bonds of a crystal determine the substance’s properties. Describe and give examples of mineral crystals.

Vocabulary Word Mineral

Mineral Properties A mineral is a naturally occurring solid. It has a crystal structure and a definite chemical composition. A few are elements. Most are compounds.

Mineral Properties -- cont’d Properties include: Color Shininess Density Crystal shape Hardness Magnetism

Mineral Properties -- cont’d Minerals break into regular shapes. Splits easily easily along fat surfaces and at sharp angles. Crystals also grow in characteristic shapes. All properties depend on its chemical composition. Each mineral is different because each has a different chemical composition.

Bonding in Mineral Crystals The arrangement of particles in a mineral and the kind of bonds holding them together determine properties such as crystal shape, hardness, and the way the crystal breaks apart.

An Ionic Crystal Example is Halite. Made of sodium chloride. Soft. Easily dissolved. Even breaks

Covalent Crystal Example is Quartz. Covalent bonds are strong. Won’t dissolve in water. Hard No defined lines of weakness.

Homework Workbook 4.3 (due 12/16) No vocabulary quiz!!