An element is a simple type of substance. More than 100 elements have been identified. They can be either solid, liquid or gas. Hydrogen and oxygen are two gases that are elements. When elements are combined, they form a compound, a substance that is a combination of two or more elements. When hyrdogen and oxygen are combined, they form the compound of water. Sugar is also a compound. It is made up of water and carbon, another element. If you heat sugar, it turns brown and sticky and eventually turns into a black solid, which is also carbon. Water vapor, in the form of hydrogen and oxygen gas, escapes into the air.
Almost all elements can be found in the Earth’s crust. Most of the crust is comprised of eight elements: oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium. These elements comprise most of the rocks we find on the surface of the Earth.
Quartz, shown at right, is a compound made up of two oxygen atoms and one silicon atom.
Question
What is the difference between an element, a compound, and a mineral?
