> when you combine [[Element|Elements]] together [[Chemistry|Chemically]] - substance composed of 2 or more **different** [[Element|Elements]], can be [[Covalent Bonds|Covalently Bonded]] or [[Ionic Bonds|Ionically Bonded]] - note there has to be different [[Element|Elements]], not just 1 - bound together in fixed ratios https://www.thescienceofeverything.net/e/episode-9-matter-and-molecules/ https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:chemical-bonding/x2613d8165d88df5e:covalent-bonds/a/molecules-salts-compounds-and-chemicals-what-s-the-difference