Compounds

Definition

Compounds are substances formed when two or more different elements chemically bond together in fixed proportions. They have unique properties distinct from their constituent elements.

5 Must Know Facts For Your Next Test

1. Compounds are always composed of atoms from two or more different elements.
2. The properties of a compound differ from the properties of the individual elements that make it up.
3. Compounds can be broken down into simpler substances by chemical means but not by physical means.
4. Water (H₂O) and carbon dioxide (CO₂) are common examples of compounds.
5. The type of bonds holding the atoms together in a compound can be ionic, covalent, or metallic.

Review Questions

• What differentiates a compound from a mixture?
• How do the properties of a compound compare to its constituent elements?
• Give two examples of compounds and explain their composition.

Related terms

Element: A pure substance consisting entirely of one type of atom.

Molecule: The smallest unit of a chemical compound that retains its chemical properties.

Ionic Bond: A type of chemical bond formed through the electrical force between oppositely charged ions.