A substance made up of atoms of two or more different elements joined by chemical bonds.

• A. Element
• B. Solution
• C. Compound
• D. Mixture

Answer: (C)

A compound is a substance formed when two or more different elements are chemically bonded. When atoms join by chemical bonds, they form a new substance with a definite composition and properties that are different from the starting elements. For example, water comes from hydrogen and oxygen bonded in a specific 2:1 ratio to make H2O, and table salt comes from sodium and chlorine bonded to form NaCl. The bonds lock the elements into a fixed arrangement, so you can’t just mix the elements together to get the compound without forming those bonds.

In contrast, an element contains only one type of atom, a mixture is a physical blend of substances that are not bonded (so they can be separated by physical means), and a solution is a homogeneous mix where the components are dispersed but not chemically bonded into a new substance.