An element consists of what?

• A. Two or more different elements bound together
• B. One kind of atom
• C. A mixture of atoms and molecules
• D. A compound with fixed ratio

Answer: (B)

An element is a pure substance made of one kind of atom. That means every particle in the substance is atoms of the same element, even if those atoms pair up to form molecules (like O2 or N2); the essential idea is that all the atoms are identical in type.

So the statement that best captures what an element consists of is “one kind of atom.” The other ideas describe substances that are not elements: two or more different elements bound together form a compound, a mixture is a blend of substances not held together by chemical bonds, and a compound with a fixed ratio is also a compound, not an element.