The term for an element that cannot be broken down into simpler substances is a chemical element. Elements are the basic building blocks of matter and are listed in the periodic table. Each element is defined by its number of protons, known as the atomic number, and possesses unique properties. Examples of chemical elements include oxygen, carbon, and iron. Understanding elements is fundamental in chemistry and helps explain how substances interact, their reactivity, and the formation of compounds. This foundational knowledge is crucial for advancements in various scientific fields, including materials science, biology, and environmental studies.