Which term refers to a chemical substance composed of two or more different elements?

The term that refers to a chemical substance composed of two or more different elements is a compound. Compounds are formed when atoms of different elements chemically combine in fixed proportions. This process alters the properties of the individual elements, resulting in a substance that has its own unique characteristics distinct from those of the separate elements.

For example, water (H₂O) is a compound made up of hydrogen and oxygen. In a compound, the elements are bonded together, which gives the compound specific chemical properties and behavior, making it different from the elements that constitute it.

Understanding the distinction between compounds and mixtures is important as well. Mixtures contain two or more substances that are physically combined and can be separated by physical means, while compounds involve a chemical bond between elements. Similarly, elements are pure substances that cannot be broken down into simpler substances by chemical means, making them the fundamental building blocks of matter.