What is the primary distinction between an element and a compound?

The primary distinction between an element and a compound lies in their composition. An element is defined as a pure substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom and is represented on the periodic table. In contrast, a compound is a substance formed when two or more different elements chemically bond together in fixed proportions, resulting in a new substance with properties distinct from those of its constituent elements.

Understanding this distinction clarifies elements' role as the basic building blocks of matter and compounds as combinations of these building blocks, showcasing the diversity of chemical substances. The other options present incorrect interpretations of the fundamental concepts of elements and compounds, such as misclassifying an element as a mixture or incorrectly stating the nature of their composition.