Elements, Compounds, and Mixtures
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.
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.