Ntawm deb ntawm lub luag haujlwm kawg ntawm cov tshuaj lom neeg ntawm lub koom haum ntawm lub ntiaj teb no yog ua si los ntawm cov txheej txheem ntawm kev sib txuas ntawm cov qauv sib txuas, kev sib tshuam. Feem ntau ntawm cov khoom yooj yim, uas yog cov hlau tsis muaj hlau, muaj covalent uas tsis yog-polar hom ntawv cog lus, tshwj tsis yog cov roj inert. Cov hlau hauv lawv daim ntawv dawb huv muaj txoj hauv kev tshwj xeeb ntawm kev sib txuas, uas tau pom los ntawm kev sib raug zoo ntawm cov hluav taws xob dawb hauv crystal lattice.
Txhua yam tshuaj (tshwj tsis yog qee cov organic) muaj covalent polar chemical bonds. Hom thiab piv txwv ntawm cov tebchaw no yuav tau tham hauv qab no. Nyob rau lub sijhawm no, nws yuav tsum paub seb tus yam ntxwv ntawm lub atom cuam tshuam rau lub polarization ntawm daim ntawv cog lus.
Electronegativity
Atoms, los yog lawv cov nuclei (uas, raws li peb paub, raug nqi zoo), muaj peev xwm nyiam thiab tuav electron ceev, tshwj xeeb tshaj yog thaum tsim ib daim ntawv cog lus tshuaj. Cov cuab yeej no hu ua electronegativity. Nyob rau hauv lub periodic table, nws tus nqi loj hlob nyob rau hauv lub sij hawm thiab lub ntsiab subgroups ntawm lub ntsiab. Tus nqi ntawm electronegativity tsis tas li thiab tuaj yeem hloov pauv, piv txwv li, thaum hloov hom hybridization uasatomic orbitals.
Tshuaj lom neeg daim ntawv cog lus, hom thiab cov piv txwv uas yuav qhia hauv qab no, los yog, qhov chaw hauv cheeb tsam lossis ib feem ntawm qhov kev hloov pauv ntawm cov nyiaj no rau ib qho ntawm cov neeg koom nrog, tau piav qhia meej los ntawm cov yam ntxwv ntawm electronegative ntawm ib lossis lwm lub caij. Kev hloov pauv tshwm sim rau lub atom uas nws muaj zog dua.
Covalent non-polar bond
Cov "formula" ntawm covalent non-polar daim ntawv cog lus yog qhov yooj yim - ob lub atoms ntawm tib yam sib sau ua ke cov electrons ntawm lawv cov valence plhaub rau hauv ib khub. Xws li ib khub yog hu ua sib koom vim nws sib npaug ntawm ob tus neeg koom hauv kev khi. Nws yog ua tsaug rau kev sib raug zoo ntawm electron ceev nyob rau hauv daim ntawv ntawm ib tug khub ntawm electrons uas lub atoms dhau mus rau ib tug ruaj khov lub xeev, raws li lawv ua tiav lawv cov sab nraud hluav taws xob theem, thiab cov "octet" (los yog "ob npaug" nyob rau hauv cov ntaub ntawv ntawm. ib qho yooj yim hydrogen tshuaj H 2, nws muaj ib qho s-orbital, uas yuav tsum tau ob lub electrons ua kom tiav) yog lub xeev ntawm theem sab nraud uas tag nrho cov atoms aspire, txij li nws sau sib haum rau lub xeev nrog lub zog tsawg kawg nkaus.
Ib qho piv txwv ntawm daim ntawv cog lus uas tsis yog-polar covalent muaj nyob rau hauv cov khoom tsis muaj zog thiab, txawm li cas los xij nws yuav zoo li txawv txawv, tab sis kuj muaj nyob rau hauv cov organic chemistry. Hom kev sib cog lus no muaj nyob rau hauv tag nrho cov khoom yooj yim - tsis yog hlau, tshwj tsis yog rau cov pa roj carbon monoxide, txij li qib valence ntawm cov pa roj atom tau ua tiav thiab muaj octet ntawm electrons, uas txhais tau hais tias kev sib txuas nrog ib qho zoo sib xws tsis ua. kev nkag siab rau nws thiab tseem tsis tshua muaj zog muaj txiaj ntsig. Nyob rau hauv cov organics, non-polarity tshwm sim nyob rau hauv ib tug neeg moleculesib tug qauv thiab yog conditional.
Covalent polar bond
Ib qho piv txwv ntawm qhov tsis yog-polar covalent daim ntawv cog lus yog txwv rau ob peb lub molecules ntawm cov khoom yooj yim, thaum cov tshuaj dipole nyob rau hauv uas cov electron ceev yog ib nrab hloov mus rau ib tug ntau electronegative keeb yog feem coob. Ib qho kev sib xyaw ntawm atoms nrog cov txiaj ntsig electronegativity sib txawv ua rau muaj kev sib raug zoo. Hauv particular, bonds hauv organics yog covalent polar bonds. Qee lub sij hawm ionic, inorganic oxides kuj yog polar, thiab nyob rau hauv ntsev thiab acids, hom ionic ntawm binding predominates.
Raws li qhov xwm txheej hnyav ntawm kev sib txuas ntawm cov polar, cov ionic hom ntawm cov tebchaw yog qee zaum txiav txim siab. Yog hais tias lub electronegativity ntawm ib qho ntawm cov ntsiab lus yog siab dua li ntawm lwm yam, lub electron khub yog kiag li hloov los ntawm daim ntawv cog lus chaw rau nws. Qhov no yog li cas kev sib cais rau hauv ions tshwm sim. Tus uas siv ib khub electron hloov mus ua ib qho anion thiab tau txais qhov tsis zoo, thiab tus uas poob ib qho hluav taws xob hloov mus ua ib qho cation thiab ua zoo.
Piv txwv ntawm cov tshuaj tsis muaj sia nrog covalent non-polar bond type
Cov khoom nrog covalent tsis-polar daim ntawv cog lus yog, piv txwv li, tag nrho cov roj binary molecules: hydrogen (H - H), oxygen (O=O), nitrogen (hauv nws cov molecule 2 atoms txuas nrog triple daim ntawv cog lus. (N ≡ N)); Cov kua thiab cov khib nyiab: chlorine (Cl - Cl), fluorine (F - F), bromine (Br - Br), iodine (I - I). Raws li cov complex tshuaj muaj xws li atoms ntawm txawv ntsiab, tab sis nrog tiag tiag tib yamTus nqi electronegativity, piv txwv li, phosphorus hydride - pH3..
Organics thiab non-polar binding
Nws yog qhov tseeb tias tag nrho cov organic teeb meem yog complex. Cov lus nug tshwm sim, yuav ua li cas thiaj li muaj ib daim ntawv cog lus uas tsis yog-polar nyob rau hauv cov khoom siv complex? Cov lus teb yog yooj yim heev yog tias koj xav tias me ntsis logically. Yog hais tias lub electronegativity qhov tseem ceeb ntawm cov ntsiab lus sib txawv insignificantly thiab tsis tsim ib lub sij hawm dipole nyob rau hauv lub compound, xws li ib daim ntawv cog lus yuav suav hais tias yog nonpolar. Qhov no yog raws nraim qhov xwm txheej nrog carbon thiab hydrogen: tag nrho C-H daim ntawv cog lus nyob rau hauv cov organics raug suav hais tias tsis yog-polar.
Ib qho piv txwv ntawm daim ntawv cog lus uas tsis muaj polar yog ib qho molecule ntawm methane, cov organic compound yooj yim tshaj plaws. Nws muaj ib tug carbon atom, uas, raws li nws valence, yog kev cob cog rua los ntawm ib tug bonds nrog plaub hydrogen atoms. Qhov tseeb, cov molecule tsis yog dipole, vim tias tsis muaj qhov chaw ntawm cov nqi hauv nws, rau qee qhov vim yog cov qauv tetrahedral. Cov electron ceev yog sib npaug.
Ib qho piv txwv ntawm qhov tsis yog-polar covalent daim ntawv cog lus muaj nyob rau hauv ntau cov organic compounds. Nws yog pom tau hais tias los ntawm cov teebmeem mesomeric, piv txwv li kev tshem tawm ntawm electron ceev, uas sai sai ploj mus raws cov saw hlau. Yog li, nyob rau hauv lub hexachloroethane molecule, C-C daim ntawv cog lus yog tsis-polar vim lub uniform rub ntawm electron ceev los ntawm rau chlorine atoms.
Lwm hom txuas
Ntxiv rau cov nyiaj cog lus, uas, los ntawm txoj kev, kuj tuaj yeem ua raws li tus neeg txais kev pabcuam, muaj ionic, metallic thiabhydrogen bonds. Cov yam ntxwv luv luv ntawm ob qhov kawg tau nthuav tawm saum toj no.
Hydrogen daim ntawv cog lus yog ib qho kev sib cuam tshuam ntawm electrostatic kev sib cuam tshuam uas tau pom yog tias cov molecule muaj hydrogen atom thiab lwm yam atom uas tsis muaj electron khub. Hom kev sib txuas no yog qhov tsis muaj zog dua li lwm tus, tab sis vim qhov tseeb tias ntau ntawm cov nyiaj no tuaj yeem tsim hauv cov khoom, nws ua rau muaj txiaj ntsig zoo rau cov khoom ntawm cov khoom sib xyaw.
