Compounds: Basic Information About Ionic Compounds

A compound is a type of matter that can be broken down into simpler substances. A compound is made up of more than one type of element chemically combined to form a new substance with its own identity and properties. The number of different types of compounds is nearly infinite. Iron oxide, rust, is an example of a compound. It contains atoms of iron and oxygen. But these atoms are joined together in a way that converts them into something new with different properties. We can simplify iron oxide by converting it back into the elements iron and oxygen.

Ionic Compounds

Description:

Ionic compounds are composed of positively and negatively charged ions and are held together by electrostatic attractions. Ionic compounds do not contain molecules. Instead, because opposite charges attract one another, the ions stack themselves in crystals such that positive ions are surrounded by negative ions, and vice versa.

Identification:

Students can identify a compound as being ionic from either the name or the formula. Metals form positive ions relatively easily, and non-metals tend to form negative ions. Hydrogen, H⁺¹, and ammonium ion, NH₄⁺¹, are the only common positive ions that do not contain a metal. To identify a compound as being ionic, scan the name or the formula and identify the elements. If the compound contains a metal (or the ammonium ion) and at least one non-metal, it is almost always an ionic compound. Compounds that contain the hydrogen ion are acids, which we will discuss separately.

This site was last updated 08/01/06