_________ is the simplest form of chemical matter.

• A. An Element
• B. A Compound
• C. A Molecule
• D. A Mixture

Answer: (A)

The simplest form of chemical matter is an element. An element is a pure substance that contains only one type of atom and cannot be broken down into simpler substances by chemical reactions. It is the fundamental building block from which all other substances are formed. Compounds are made of two or more elements bonded together and can be decomposed into those elements; a molecule is the smallest unit of a substance that retains its properties (and can be a molecule of an element, like O2, or of a compound); and a mixture is a physical combination of substances without chemical bonding. So, because an element cannot be chemically broken down into simpler substances, it is the simplest form of chemical matter.