Classifying Matter

Elements, Compounds, and Mixtures

Pure Sustances

A pure substance is matter that is composed of only one substance. Some examples are; gold, neon, and salt.


An element is a pure substance that cannot be separated into a simpler substance by chemical or physical means. Some elements are more reactive than others, such as the alkali metals, and some are not reactive at all, like the noble gasses. Some examples of elements are; sodium, beryllium, and silver.


A compound is pure substance composed of two or more different elements joined by chemical bonds. Some of the characteristics of compounds are:

  • Made of elements in a specific ratio that is always the same.
  • Has a chemical formula.
A compound can only be separated chemically, not physically.

Some common compounds are salt, pure water, and baking soda.


A mixture is a combination of two or more pure substances that are not chemically bonded. Some common examples of mixture are cereal, sand, and jelly beans. Cereal can be broken down by taking the cereal out of the milk. This can be done because the milk and cereal are not chemically bonded, but physically bonded.