Final answer:
An element is a pure substance composed of only one type of atom. A compound is a pure substance composed of two or more different types of atoms chemically bonded together. A mixture is a combination of two or more substances.
Step-by-step explanation:
An element is a pure substance composed of only one type of atom. Examples of elements include hydrogen, oxygen, and carbon.
A compound is a pure substance composed of two or more different types of atoms chemically bonded together. Water (H2O) and carbon dioxide (CO2) are examples of compounds.
A mixture is a combination of two or more substances that are not chemically bonded together. A mixture can be either homogeneous or heterogeneous. In a homogeneous mixture, the composition is uniform throughout, while in a heterogeneous mixture, the composition is not uniform.