Enye yezimpumelelo ezinkulu ezingeni lesayensi kwaba ukuhlukaniswa nokuhlelwa kwezinto. Ukufundwa kwezakhiwo zezindaba kusukela esikhathini sososayensi bamakhemikhali, ososayensi bakule ndawo babehlala benombono ngokubaluleka kokusungula uhlelo lokuhlukanisa, oluzovumela ukuphathwa okuhlelekile kwezinto ezazaziwa ngaleso sikhathi.
Ukusuka lapho, ngemuva kwemizamo eminingi, itafula elaziwa kakhulu lama-electronegativities lakhiwa, elaziwa nangokuthi ithebula lezikhathi likaMendeleev, okuyisistimu yokuhlela nokuhlela esebenza kahle kakhulu esinayo kuze kube manje. Kuyo izakhi zihlelwe ngaphakathi ukusebenza kwe-electronegativities yabo, okuyisilinganiso samandla ama-electron egobolondweni lawo lokugcina ukuhlangana namanye ama-athomu, kodwa sizokhuluma ngalokho.
Kuyini i-electronegativity?
Ngaphambi kokungena ngokugcwele esihlokweni, kubalulekile ukucacisa ukuthi yonke into yakhiwe ngama-athomu, njengoba kuchazwe nguJohn Dalton ngo-1803. ama-proton ajikeleza emjikelezweni we-elliptical, futhi kungama-electron akhona kusendlalelo sokugcina sesici esimweni saso sokuhlanganiswa inquma umthamo wento ngayinye ukwakha izinhlanganisela. Yilokhu okuchaza i-electronegativity, ikhono le-athomu lokuhlanganisa ngamabhondi namanye ama-athomu.
Le nqubo ichazwa isenzo sezinto ezimbili:
- Ubunzima be-Atomic: Ubani inani eliphelele lama-proton nama-neutron ku-athomu elilodwa.
- Ama-Valence electron: Izinhlayiya ezikhokhiswe kabi ezitholakala kusendlalelo sokugcina se-athomu, okuyinani lezinhlayiya ezitholakalayo zokwenza ukushintshaniswa ekwakhekeni kwamakhemikhali.
Ukuthuthukiswa kwetafula le-electronegativity
Ekufuneni kwabo ukuhlukaniswa okwanele kwezakhi, ososayensi abaningi baveza imibono ngokuthi yini engaba uhlelo olufanele, lapho izakhi zingatholwa ngendlela ehlelekile, kucatshangelwa izakhiwo zazo. Ososayensi abalandelayo benze iminikelo ebalulekile ebambe iqhaza ekwakhiweni kwetafula lamanje lama-electronegativities:
- U-Antoine Lavoisier: Ukuhlukaniswa okwenziwe ngusosayensi wezakhi kwenziwa ngokuzithandela, ngaphandle kokubheka noma yiziphi izindlela zokuhlukanisa, ngakho ukuhlukaniswa kwakhe akuphumelelanga kakhulu.
- UJohann Dobereiner: Lo sosayensi waziwa ngokuthuthukisa oziqu abathathu abanegama lakhe. Wakha isifundo lapho aqoqa khona izinto eqenjini labathathu, ethola lapho eqhathanisa ukuthi ubukhulu babo be-athomu (ezinqunywa kusetshenziswa i-spectrometer yesisindo), namanani athile wezinto zawo ezibonakalayo, ayehlobene. Ngakho-ke, bangabikezelwa ngokusebenzisa ukulinganisa kwezibalo. Usokhemisi waseBrithani UJohn newlands, wasebenza ngesisekelo esakhiwe nguDobereiner, futhi ngaleyo ndlela wakwazi uku-oda izakhi etafuleni ngokuqoqwa kwama-elementi ezinhlayiyana ze-athomu ngobuningi; Ngaleli qembu, abaseBrithani bafuna ukwenza itafula lapho kunephethini yokuphindaphinda ngezikhathi ezithile ze izakhiwo zomzimba zezakhi. Njengoba ukuphindwaphindwa okunjalo kwaqoqwa ngezinto ezizungeze eziyi-8, zazichazwe ngegama le- "Umthetho wama-octave".
- U-Lothar Meyer: Uyaziwa ngokwandisa ulwazi emkhakheni wokutadisha ubudlelwane bezakhiwo zomzimba nezakhiwo ze-athomu zezakhi. Umsebenzi wakhe wawuhambisana nomsebenzi owakhiqizwa nguMendeleev.
- UDmitri Mendeleev: Kususelwa kokuthunyelwa kwe- umthetho wezikhathi ezithile, lo sosayensi wenza umsebenzi ophumelela kakhulu wokuhlukanisa izinto, osasebenza (ngokuguqulwa, lapho kunezelwe khona izinto ezintsha ezitholakele. Uhlukanise izakhi ngokubhekela amandla azo, futhi waba nombono wokushiya amabhokisi lapho kungekho nto fit, ubona ukuthi kuzolingana into ebingakatholakali.Izakhi ezaziwayo ezeqe amapharamitha we-oda zaphawulwa ngokwehlukana, esikhundleni sokufakwa ngokungafanele (iphutha elenziwe nguLavoisier neNewlands). Ngokuphathelene nokungakhethi kwamandla ngaphakathi kwetafula, umthetho ojwayelekile uthi: I-Electronegativity yinani elikhulayo njengoba siya ngakwesokunene setafula, sibona ukwehla lapho siya kwesobunxele. Izinto ezingaphezulu kwetafula zinamanani aphezulu we-electronegativity.
Isikali se-Electronegativity
Amanani ahlukile we-electronegativity anquma uhlobo lwebhondi olwakhiwe, ngakho-ke, ukutadisha le nqubo bekuyinto enentshisekelo kuyo, futhi kwenziwa amaposi amabili:
Isikali sikaPauling: Ngokwezifundo zikaPauling, kwasungulwa ukuthi i-electronegativity iyimpahla eguquguqukayo, ngoba kuya ngesimo se-oxidation sento leyo. Ukubona kwakhe kwamvumela ukuthi anqume ukuthi, uma kwenziwa ukukhipha, noma umehluko, wama-electronegativities, singabikezela uhlobo lwebhondi elizokwakhiwa, njengoba esungule isikali:
- Isibopho se-Ionic: I-Electronegativity gradient inkulu kune noma ilingana no-1.7. Lesi sibopho sivame ukwenzeka phakathi kwezakhi zensimbi nezingezona ezensimbi.
- Isibopho se-Covalent: Lapho umehluko usezingeni lika-1.7 kuye ku-0.4. Kuvamile ukuwabona kumakhemikhali angenasici.
- Isixhumanisi sePolar: Ngokwehluka okulingana noma okungaphansi kuka-0.4.
Isikali seMulliken: Kususelwa ekuhlanganyeleni kwe-elekthronikhi kwezinto, ezichaza ukuthambekela kwazo kokuthola inkokhiso engemihle, okuyilokho okuchaza amandla ento yokwamukela ama-electron. Isebenza futhi ngamakhono e-ionic, nawo lawo anquma ukubekeka kwento ukuze kutholakale imali enhle (izinto ezinamacala afanele yizo ezinikela ngama-electron kugobolondo lawo lokugcina). Lesi sikali sisebenza ngamanani amaphakathi.