Saurabh kush waha
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Dalton's atomic theory proposed that all matter is composed of indivisible and indestructible atoms that are the fundamental building blocks. Atoms of the same element are identical in size and mass, while atoms of different elements vary. Compounds form through combinations of atoms in fixed ratios, and chemical reactions involve rearrangements of atoms. Dalton's theory was the first truly scientific explanation of atoms and helped establish modern atomic theory.
Saurabh kush waha
- 1. Topic- Dalton’s atomic theory
- 2. KEY POINT • DALTON’SATOMICTHEORYPROPOSEDTHATALL MATTERWASCOMPOSED OF ATOMS,INDIVISIBLEANDINDESTRUCTIBLEBUILDINGBLOCKS.WHILE ALL ATOMSOF AN ELEMENTWEREIDENTICAL,DIFFERENTELEMENTSHAD ATOMSOF DIFFERINGSIZE ANDMASS. • DALTON’SATOMICTHEORYALSOSTATEDTHATALLCOMPOUNDSWERE COMPOSEDOFCOMBINATIONSOF THESEATOMSIN DEFINEDRATIOS. • DALTONALSOPOSTULATEDTHATCHEMICALREACTIONSRESULTEDIN THEREARRANGEMENTOF THEREACTINGATOMS.
- 3. TERMS • ATOMTHESMALLESTPOSSIBLEAMOUNTOF MATTERTHATSTILLRETAINS ITSIDENTITYASA CHEMICALELEMENT,NOWKNOWNTOCONSISTOFA NUCLEUSSURROUNDEDBYELECTRONS. • ATOMICMASSUNITTHESTANDARDUNITTHATIS USEDFORINDICATING MASSOFANATOM.
- 4. HISTORY OF DALTON’S ATOMIC THEORY ALTHOUGHTHECONCEPTOFTHEATOMDATESBACKTOTHEIDEASOFDEMOCRITUS,THEENGLISH METEOROLOGISTANDCHEMISTJOHNDALTONFORMULATEDTHEFIRSTMODERNDESCRIPTIONOF ITASTHEFUNDAMENTALBUILDINGBLOCKOFCHEMICALSTRUCTURES.DALTONDEVELOPEDTHE LAWOFMULTIPLEPROPORTIONS(FIRSTPRESENTEDIN1803)BYSTUDYINGANDEXPANDINGUPON THEWORKSOFANTOINELAVOISIERANDJOSEPHPROUST. PROUSTHADSTUDIEDTINOXIDESANDFOUNDTHATTHEIRMASSESWEREEITHER88.1%TINAND 11.9%OXYGENOR78.7%TINAND21.3%OXYGEN(THESEWERETIN(II)OXIDEANDTINDIOXIDE RESPECTIVELY).DALTONNOTEDFROMTHESEPERCENTAGESTHAT100GOFTINWILLCOMBINE EITHERWITH13.5GOR27GOFOXYGEN;13.5AND27FORMARATIOOF1:2.DALTONFOUNDANATOMIC THEORYOFMATTERCOULDELEGANTLYEXPLAINTHISCOMMONPATTERNINCHEMISTRY– INTHE CASEOFPROUST’STINOXIDES,ONETINATOMWILLCOMBINEWITHEITHERONEORTWOOXYGEN ATOMS.
- 5. Dalton also believedatomic theory couldexplainwhywaterabsorbed different gasesin different proportions: for example, he found that water absorbed carbondioxide far better than it absorbed nitrogen. Daltonhypothesizedthis was due to the differences in the mass and complexityof the gases’ respective particles. Indeed, carbondioxide molecules (CO2) are heavier and larger thannitrogen molecules (N2). Dalton proposed that each chemical element is composed of atoms of a single, unique type, and though theycannot be alteredor destroyed by chemical means, theycan combineto form more complex structures (chemical compounds). Since Dalton reachedhis conclusionsby experimentation and examination of the results in an empirical fashion, this marked the first trulyscientific theoryof the atom.
- 6. DALTON’S ATOMIC THEORY THEMAINPOSTULATESOFDALTON’SATOMICTHEORY WERE: • EVERYTHINGIS COMPOSEDOF ATOMS,WHICHARETHEINDIVISIBLEBUILDINGBLOCKSOF MATTERANDCANNOTBE DESTROYED. • ALLATOMSOF AN ELEMENTAREIDENTICAL. • THEATOMSOF DIFFERENTELEMENTSVARYIN SIZEANDMASS. • COMPOUNDSAREPRODUCEDTHROUGHDIFFERENTWHOLE-NUMBERCOMBINATIONSOF ATOMS. • A CHEMICALREACTIONRESULTSIN THEREARRANGEMENTOFATOMSIN THEREACTANTAND PRODUCTCOMPOUNDS. ATOMICTHEORYHASBEENREVISEDOVERTHEYEARSTOINCORPORATETHEEXISTENCEOFATOMIC ISOTOPESANDTHEINTERCONVERSIONOFMASSANDENERGY.IN ADDITION,THEDISCOVERYOF SUBATOMICPARTICLESHASSHOWNTHATATOMSCANBE DIVIDEDINTOSMALLERPARTS.HOWEVER, DALTON’SIMPORTANCEIN THEDEVELOPMENTOF MODERNATOMICTHEORYHASBEEN RECOGNIZEDBY THEDESIGNATIONOF THEATOMICMASSUNITAS A DALTON