Kunqunywa Valence samakhemikhali

Ulwazi isakhiwo zama-athomu nezinhlayiyana ezincane ekhulwini XIX abakwazi ukuchaza isizathu lapho inombolo ezithile zama-athomu izibopho nezinye izinhlayiya. Kodwa imibono yososayensi ngaphambi kwesikhathi babo, kanye Valence namanje lafundvwako njengenye izimiso eziyisisekelo chemistry.

Kusukela umlando welithi "Valence samakhemikhali"

Ezivelele British wemithi XIX leminyaka Edvard Franklend owaqamba igama elithi "ukuxhumana" e ukusetshenziswa kwesayensi ukuchaza ukuxhumana kwama-athomu nomunye. Scientific waphawula yini ukuthi abanye izakhi zamakhemikhali yakha compounds nge esilinganayo nezinye ama-athomu. Ngokwesibonelo, i-nitrogen inamathela ama-athomu amathathu hydrogen molecule ammonia.

Ngo-May 1852 Frankland ukubeka phambili umbono wokuthi kukhona isibalo esithile izibopho ikhemikhali i-athomu ungakheka nezinye izinhlayiya ezincane zendaba. Frankland wasebenzisa inkulumo ethi "i-force yokuxhuma" ukuchaza lokho kamuva okwakuzoba ubizwe Valence. wemithi British owasungulwa njengoba izibopho zamakhemikhali yakha athomu ezakhi ngabanye owaziwayo Maphakathi nekhulu XIX. Umsebenzi Frankland kwaba isandla esibalulekile emkhakheni wesayensi yokuthakwa kwamakhemikhali yesimanje kwesakhiwo.

ukuthuthukiswa ukubukwa

wemithi German FA Kekule wazibonakalisa ngo-1857 ukuthi carbon kuyinto chetyrehosnovnym. Ngo kwakwakhe yayo elula - methane - kuphakama ngenxa 4 ama-athomu ye-hydrogen. Igama elithi "basicity" Usosayensi lasetshenziswa ukuze kubhekiselwe endaweni izakhi izakhiwo ukuxhuma izinombolo ezihleliwe nezinye izinhlayiya. ERussia, idatha ku isakhiwo ndaba systematized A. M. Butlerov (1861). ukuqhubeka imfundiso yokuziphendukela chemical isibopho sizila izimfundiso ushintsho ngezikhathi property izakhi. Umbhali wayo - omunye oluvelele Usokhemisi waseRussia D. I. Mendeleev. It wafakazela ukuthi Valence samakhemikhali e zezakhi, kanye nezinye izakhiwo kunqunywa isikhundla okuyinto hlala ohlelweni gqwa.

Ukumelwa sokuqhafaza Valence namakhemikhali kunenze nisondelane

Kungenzeka zishintshe nangama - omunye kokufaneleka undoubted ka Valence theory. Imodeli uqala ukuvela ngo-1860, futhi kusukela ngo-1864 ubelokhu esebenzisa amafomula kwesakhiwo emelela chemical uphawu circumferential ngaphakathi. Phakathi izimpawu ama-athomu dash ezikhonjiswe chemical isibopho, futhi inani lemigqa uyalingana Valence. Ngaleyo minyaka efanayo, kwenziwa imodeli sharosterzhnevye lokuqala (bheka. Photo ngakwesokunxele). Ngo 1866 Kekule ezihlongozwayo iphethini stereochemical zama-athomu carbon ngesimo a Tetrahedron, okuyinto akufaka encwadini ebhukwinitifundvo yakhe "Organic Chemistry".

Valence samakhemikhali, futhi ukuvela ubudlelwano ufundwa G. Lewis, wanyathelisa wakhe ngo-1923 ngemva kwatholakala i-electron. Ngakho ngokuthi omubi icala ezinhlayiyeni ezincane, okuyiwona ayingxenye ebaluleke kakhulu emagobolondweni athomu. Encwadini yakhe ethi, Lewis esetshenziswa iphuzu emhlabeni izinhlangothi ezine uphawu chemical ngoba nombukiso electron Valence.

Valency hydrogen nomoya-mpilo

Ngaphambi ukudalwa uhlelo ngezikhathi Valence samakhemikhali e zezakhi senziwa ukuba ziqhathaniswa athomu lapho yaziwa. Hydrogen nomoya-mpilo, akhethwa njengoba inkomba. Esinye isici chemical ikhangwa noma esikhundleni inombolo ethile H athomu, futhi O.

Ngale ndlela, izakhiwo babezimisele endaweni compounds monovalent ne-hydrogen (the valency timphawu wesibili ebekwe yesi-Roman):

• HCl - chloro (I):
• H ₂ O - mpilo (II);
• NH ₃ - nitrogen (III);
• CH ₄ - carbon (IV).

I oxides of K ₂ O, CO, N ₂ O _3, uSio _2, SO ₃ abangu kunqunywa Valence of izinsimbi kanye nonmetals oksijini, kuphindaphindwe kabili inani ama-athomu attachable O. Etholwe elandelayo amanani: K (I), C ( II), N (III) , Si (IV), S (VI).

Indlela ukucacisa Valence samakhemikhali

Kukhona imithetho kumiswa izibopho zamakhemikhali ne ezivamile electron ngazimbili:

• Ejwayelekile hydrogen Valence - I.
• Kuvamile-mpilo Valence ka - II.
• Ukuze izakhi nonmetals-ephansi Valence kungenziwa kunqunywa ifomula 8 - № iqembu ngazo ohlelweni gqwa. Ephakeme, uma kungenziwa kunqunywa inani iqembu.
• Ukuze ohlangothini tincenye subgroups esiphezulu kungenzeka valency kuyafana inani amaqembu ishadi lesikhathi.

Ukunqunywa Valence samakhemikhali kwakwakhe ifomula Kwenziwa ngokusebenzisa algorithm ezilandelayo:

1. Record phezu amakhemikhali ajwayelekile Inani elaziwayo esinye sezici. Ngokwesibonelo, ngo-MN ₂ O _7-mpilo valency kuyinto II.
2. Bala inani, okumele siphindwe Valence we-athomu ye efanayo element kwamakhemikhali molecule 2 * 7 = 14.
3. Anqume valency we umbandela wesibili, okuyiwona wona alwaziwa. Hlukanisa etholwe Sec. 2 Inani ngenani MN zama-athomu engqamuzaneni.
4. 14: 2 = 7. Valence of oxide manganese e eliphakeme yayo - VII.

valency unomphela futhi variable

Valence amagugu hydrogen nomoya-mpilo zihlukile. Ngokwesibonelo, nesibabule elibona nxazonke H ₂ S divalent, njengoba ikufomula SO ₃ - hexavalent. I monoxide carbon ihlangana oksijini, CO CO ₂ dioxide. Egcekeni lokuqala Valence C II, futhi ngo-yesibili - IV. Inani elifanayo e-methane CH _4.

Iningi izakhi musa abonise Valence njalo futhi variable, isib, i-phosphorus, i-nitrogen, isibabule. Ukucinga for the kwezimbangela eziyinhloko zale mkhuba kwaholela ekutheni izikhulu zibonise imfundiso yokuziphendukela kunenze nisondelane zamakhemikhali, lwati loluphatselene Valence igobolondo electron, orbitals yamangqamuzana ezinto eziphilayo. Ukuba khona amagugu ezahlukene ezifanayo kodwa ngesikhathi esifanayo etholwe ne incazelo isakhiwo zama-athomu nezinhlayiyana ezincane isikhundla.

imibono Wanamuhla Valence

Zonke ama-athomu yakhiwa nucleus omuhle sizungezwe electron omubi icala. Igobolondo elingaphandle, okuyinto akha, kuyinto sidle. Isakhiwo esiphelele iyona esitebeleni kunazo, iqukethe 8 electron (OCTET). Chemical ekwakheni ubuhlobo okuvame electron ngazimbili imiphumela bazisa evumayo ama-athomu isimo.

Rule kumiswa compounds kuwukufezeka igobolondo noma ngokuthola ama-electron kuzwakale kushaqisa ayibhangqiwe - kuncike ekutheni inqubo kulula ukuba kudlule. Uma athomu sihlinzekela ukubunjwa amakhemikhali isibopho izinhlayiya negative abangenalo pair, izibopho akha uma nje electron ayibhangqiwe. Ngokusho imiqondo zanamuhla, Valence zama-athomu ezakhi chemical - yikhono ukukhiqiza inombolo ethile covalent izibopho. Ngokwesibonelo, e-molecule, H ₂ S sulphur, hydrogen sulfide ne ozuza Valence II (-), ngoba athomu ngalinye uhlanganyela kumiswa amabhangqa amabili-electron. Isibonakaliso "-" ibonisa Luhambo umbhangqwana electron kungxenye electronegative ngaphezulu. Okungenani electronegative ukubaluleka Valence appends "+".

Lapho kuhileleke donor-acceptor indlela kule nqubo ye-electron ngazimbili elilodwa isici kanye nezinye khulula Valence orbitals.

Ukwencika Valence isakhiwo ye-athomu

Cabangela isibonelo yekhabhoni nomoya-mpilo, njengoba kuncike isakhiwo izinto Valence samakhemikhali. Periodic Table isinikeza amazwibela izici eziyisisekelo athomu carbon:

• uphawu chemical - C;
• inombolo nto - 6;
• icala yenuzi - 6;
• proton nucleus - 6;
• electron - 6, kuhlanganise 4 zangaphandle, 2 ka akha pair, 2 - ayibhangqiwe.

Uma i-athomu carbon yakha izibopho ezimbili CO monoookside ke ukusetshenziswa kwalo enikeziwe izinhlayiya negative 6 kuphela. Ukuze sizuze octets ezidingekayo ukuze umatanise 4 kwakheka izinhlayiya zangaphandle ezimbi. Carbon has a Valence ka IV (+) e dioxide futhi IV (-) e-methane.

neenomborosikhundla umoya-mpilo - 8, igobolondo Valence siqukethe electron eziyisithupha, ezimbili zazo akha ngababili zinengxenye izibopho zamakhemikhali kanye nokuxhumana nabanye kuma-atom. Ejwayelekile umoya-mpilo Valence - II (-).

Isimo valency kanye namachibi

Ezimweni eziningi kuba kulula ukusebenzisa igama elithi "degree of namachibi". Ngakho ngokuthi icala athomu ngalo uzothola uma zonke electron baye bathuthela element yokubopha izimvu, okuyinto inenani elektroootritsatelnosti ephakeme (EO). Inombolo namachibi efana elula zero. Ngu namachibi ngaphezulu EO wanezela isici "-" uphawu, ngaphansi electronegative - "+". Ngokwesibonelo, i-main iqembu nensimbi ukuze namachibi ejwayelekile futhi ion uyala lilingane nge isibonakaliso "+". Ezimweni eziningi valency kanye namachibi isimo zama-athomu enkompolo efanayo anda luqondane. Kuphela uma nokuxhumana okwengeziwe ngama-athomu electronegative isimo esihle namachibi, oluxube kabani EO ngezansi - ezingezinhle. Umqondo "Valence ka" ngokuvamile usebenza kuphela lwalezozinto ukwakheka kwama-molecule.