In chemistry, a pure element means a substance whose atoms all (or in practice almost all) have the same atomic number, or number of protons. Nuclear scientists, however, define a pure element as one that consists of only one stable isotope.

What does it mean for an element to be pure?

An element is a pure substance as it cannot be broken down or transformed into a new substance even by using some physical or chemical means. Elements are mostly metals, non-metals or metalloids. Compounds, on the other hand, are also pure substances when two or more elements are combined chemically in a fixed ratio.

Is a pure substance a mixture?

a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.