When two or more elements are combined, what is formed?

When two or more elements are combined chemically, they form a compound. A compound has distinct chemical properties that are different from the properties of the individual elements that compose it. The atoms in a compound are bonded together in fixed ratios, resulting in a substance with a unique composition and structure, exemplified by compounds like water (H₂O) or carbon dioxide (CO₂), where specific elements combine to create a new, stable substance.

In contrast, a mixture involves the physical combination of two or more substances where each retains its individual properties, meaning the components are not chemically bonded as in a compound. An example of this is a salad, where each ingredient can be differentiated. An alloy is a specific type of mixture, usually of metals, created to yield certain properties that differ from the components alone. A solution, on the other hand, is a homogeneous mixture where one substance is dissolved in another, like saltwater. Each of these categories serves to illustrate the different ways elements or substances can interact, but they distinctly differ from the formation of a compound, where a chemical bond leads to a new substance.