Oregon Cosmetology Certification Practice Exam

The simplest form of matter that cannot be broken down is called an element. An element is a substance made up of only one type of atom, and it cannot be broken down further into smaller substances. For example, gold is an element made up of gold atoms, and no matter what chemical reactions or processes it undergoes, it will always remain as gold. This makes options A, B, and D incorrect. A compound is a substance made up of two or more elements bonded together, such as water (H2O) or salt (NaCl). A molecule is the smallest unit of a chemical compound, made up of two or more atoms bonded together. An atom, while the smallest unit of an element, can still be broken down into smaller particles, such as protons, neutrons, and electrons. Therefore, only option C, element, fits the description of a substance that cannot be broken down into simpler forms.