What is an element defined as?

An element is defined as a fundamental substance that cannot be broken down into simpler forms by chemical means. This definition is key because elements are the most basic building blocks of matter; they consist of only one type of atom and are represented on the periodic table. Each element has unique properties and atomic numbers that distinguish it from other elements.

For example, hydrogen (H) is an element that consists solely of hydrogen atoms and cannot be separated into simpler substances without changing its nature, which directly supports the definition presented in the correct response. Understanding elements is crucial in the study of chemistry, as they form the basis for all compounds and mixtures, which are more complex structures formed from combinations of elements.