Final answer:
An element is a pure substance made up of only one type of atom, a compound is a substance made up of two or more elements chemically combined in a fixed ratio, and a mixture is a combination of two or more substances that are not chemically bonded together.
Step-by-step explanation:
Element:
An element is a pure substance made up of only one type of atom. Each element is represented by a unique symbol, such as H for hydrogen or O for oxygen. Examples of elements include oxygen, carbon, and gold.
Compound:
A compound is a substance made up of two or more elements chemically combined in a fixed ratio. The elements in a compound are bonded together. For example, water (H2O) is a compound made up of two hydrogen atoms bonded to one oxygen atom. Other examples include carbon dioxide (CO2) and sodium chloride (NaCl).
Mixture:
A mixture is a combination of two or more substances that are not chemically bonded together. The different substances in a mixture retain their individual properties and can be separated by physical means. Examples of mixtures include air (a mixture of gases), saltwater (a mixture of salt and water), and a salad (a mixture of vegetables).
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