Chemistry, the science of the properties, composition, and structure of substances (defined as elements and compounds), the transformations they undergo, and ...ChemistrySections&MediaEncyclopediaArticleIntroductionThescopeofchemistryAnalyticalchemistryInorganicchemistryOrganicchemistryBiochemistryPolymerchemistryPhysicalchemistryIndustrialchemistryThemethodologyofchemistryStudiesofmolecularstructureAtomsandelementsIonicandcovalentbondingIsomerismInvestigationsofchemicaltransformationsBasicfactorsEnergyandthefirstlawofthermodynamicsEntropyandthesecondlawofthermodynamicsRatesofreactionChemistryandsocietyThehistoryofchemistryPhilosophyofmatterinantiquityAlchemyPhlogistontheoryThechemicalrevolutionAtomicandmoleculartheoryOrganicradicalsandthetheoryofchemicalstructureMendeleyev’speriodiclawTheriseofphysicalchemistryElectronictheoriesofvalenceBiochemistry,polymers,andtechnologyTheinstrumentalrevolutionOrganicchemistryinthe20thcenturyChemistryinthe21stcenturyExpandLearningGuidesArticleSummaryMediaVideosImagesInteractivesAdditionalInfoAdditionalReadingMoreArticlesOnThisTopicContributorsArticleHistoryHomeScienceChemistryChemistryPrintprintPrintPleaseselectwhichsectionsyouwouldliketoprint:TableOfContentsCiteverifiedCiteWhileeveryefforthasbeenmadetofollowcitationstylerules,theremaybesomediscrepancies.Pleaserefertotheappropriatestylemanualorothersourcesifyouhaveanyquestions.SelectCitationStyleMLAAPAChicagoManualofStyleCopyCitationShareShareSharetosocialmediaFacebookTwitterURLhttps://www.britannica.com/science/chemistryMoreGiveFeedbackExternalWebsitesFeedbackCorrections?Updates?Omissions?Letusknowifyouhavesuggestionstoimprovethisarticle(requireslogin).FeedbackTypeSelectatype(Required)FactualCorrectionSpelling/GrammarCorrectionLinkCorrectionAdditionalInformationOtherYourFeedbackSubmitFeedbackThankyouforyourfeedbackOureditorswillreviewwhatyou’vesubmittedanddeterminewhethertorevisethearticle.JoinBritannica'sPublishingPartnerProgramandourcommunityofexpertstogainaglobalaudienceforyo