Izici kanye nezakhiwo zezibopho ze-covalent ezingezona ezi-polar: umhlahlandlela ophelele onezibonelo

Kusukela ekuqaleni kwezifundo ngezici zezinto, ososayensi baqala ukuqonda ukuthi kukhona amandla akwazi ukwakha izixhumanisi phakathi kwezinhlobo ezahlukene zezilwane. "Izinhlayiya ziyakhangana ngamandla," kusho u-Isaac Newton, futhi eminyakeni kamuva, ngenxa yokusungulwa kwenqwaba edumile ye-voltaic, uJöns Jakob Berzelius wakha umbono mayelana nenqubo yokuhlanganiswa kwamakhemikhali.

Ngenxa yentuthuko yocwaningo olwenziwe ososayensi abahlukahlukene, namuhla siyaqiniseka ukuthi izakhi zamakhemikhali , njengabantu, ziyasebenzisana, futhi kusukela kulesi senzo kuvela izakhiwo ezintsha, ukuhlanganiswa, ama-compound kanye nezinhlobonhlobo ezinkulu zezinguquko.

Umphumela wokuxhumana okunjalo uncike ezicini zomuntu ngamunye ze-athomu ngayinye , okuzokhawulela uhlobo lwesibopho esakhiwe, ukuzinza kwenhlanganisela, kanye nezakhiwo zayo eziningi zomzimba nezamakhemikhali. Ukuze isibopho se-covalent esingeyona i-polar senzeke ngaphakathi kwe-molecule , uhlobo oluhilelekile kumele lufane kakhulu ngokwe-electronegativity.

Izimo ezinquma ukwakheka kwezixhumanisi

Nakuba kungase kubonakale sengathi lezi zinqubo zokwakheka kwe-compound ngokubopha zenzeka ngokuzenzakalelayo nakuzo zonke izimo ezingaba khona, iqiniso liwukuthi ukubopha phakathi kwama-athomu kwenzeka kuphela lapho izimo ezizungezile zenqubo zivuma. Izici ezifana nokushisa nokucindezela zikhawulela ukwenzeka kokusabela futhi zishintsha nomphumela noma izici ze-compound eyakhiwe.

Esinye isici esibalulekile ukuhlushwa kwezinto , okunquma inani kanye nohlobo lwesakhi esizovela enkambisweni yokuhlanganiswa. Ezimweni eziningi zokusabela, ngisho nokwehluka okuncane kwesilinganiso sezinto ezisabelayo kungaholela ekwakhekeni kwemikhiqizo ehlukene noma kuvimbele ukusabela ukuthi kuqhubeke nhlobo.

Izici ngazinye zezinhlayiya , ikakhulukazi i-electronegativity yazo, i-athomu radius, kanye nokuma kwe-elekthronikhi, kunquma inani kanye nezinhlobo ezihlanganayo; futhi kunquma uhlobo lwesibopho esizokwakheka. Kumelwe sikhumbule ukuthi, ngokwesilinganiso esiphakanyisiwe nguLinus Pauling, uhlobo lwesibopho esakhiwe luncike ekwehlukeni kwe-electronegativity phakathi kwalezo zinhlobo.

• Ionic: Umehluko we-electronegativity omkhulu noma olingana no 1,7Lokhu kukhombisa ukuthi lolu hlobo lwesibopho luyisici sezinhlobo ezine-electronegativities ezihlukene kakhulu, ngakho-ke i-athomu ene-electronegative kakhulu Kukhanga kakhulu ama-electron e-valence, akhiqiza ama-ion amahle nangalungile abanjwe ndawonye ngamandla kagesi.
• I-covalent eyisikwele: Umehluko phakathi kwe- I-1,7 ne-0,5 cishe. Ngokuvamile kwakheka phakathi kwezinto ze i-electronegativity ephezulu (ikakhulukazi okungezona izinsimbi) futhi kwenzeka ukuthi inhlanganisela eyakhiwe ingumphumela we- indawo engalingani ama-electron. Elinye lama-athomu lidonsela ifu lama-electron kakhudlwana, lidala isibopho esinophawu oluthile lwe-polarity.
• I-covalent engeyona i-polar: Lokhu kwenzeka uma umehluko oqoshiwe ukhona ngaphansi noma okulingana no-0,4 – 0,5 (nakuba ezimweni eziningi cishe ilingana no-zero). Kulesi simo, ama-electron abiwa ngendlela elinganiselayo kakhulu.

Lezi zindlela zokwehluka kwe-electronegativity zisivumela ukubikezela i-bond polarity . Ikakhulukazi, amanani aphakathi kuka-0 no-0,4 ahambisana nezibopho ze-covalent ezingezona i-polar , lapho ifu le-electron lisatshalaliswa cishe ngokulinganayo phakathi kwama-athomu amabili ahlanganisiwe.

Siyini isibopho se-nonpolar covalent?

Isibopho samakhemikhali amandla ahlanganisa ama-athomu amabili. Lokhu kuxhumana phakathi kwawo kuwanika ukuzinza okukhulu kwamandla. Ngokuhlanganisa ama-athomu amaningana ngezibopho, kwakheka ama-molecule noma ama-crystalline lattices, okuyiwona ayisisekelo sayo yonke into eyaziwayo.

Ngokombono wesakhiwo, i-athomu yakhiwa yi- nucleus (ama-proton nama-neutron) kanye nefu lama -electron ahambahambayo. Lawa ma-electron, ikakhulukazi lawo asegobolondweni le-valence , yiwo ahlanganyela ekuhlanganiseni. I-athomu ehlukanisiwe ngokuvamile ayizinzile kakhulu, ngakho-ke ivame ukusebenzisana namanye ama-athomu ukuze ifinyelele ukwakheka kwe-elekthronikhi okuzinzile kakhudlwana, okuvame ukufana nokwamagesi ahloniphekile.

Njengoba kwaziwa kahle, i-nucleus yama-athomu ishajelwe kahle, ngakho-ke ukuthambekela kwemvelo kwezinhlobo ezimbili zamakhemikhali kungaba ukuxoshana. Kodwa-ke, yifu lama-electron azungeza i-nucleus elenza ukwakheka kwezibopho zamakhemikhali kube nokwenzeka, njengoba la ma-electron angabiwa noma adluliselwe phakathi kwama-athomu ahlukene.

Ukuze kwakheke isibopho, izinhlobo zamakhemikhali ezikhona kumele zihlangabezane nombandela ojwayelekile: eyodwa kumele ingabi nama-electron egobolondweni layo langaphandle, kanti enye kumele ibe nama-electron atholakalayo ukuze abelane ngawo . Lokhu kukhangana phakathi kwama-nuclei amahle kanye nefu lama-electron ahlanganyelwe kuvumela amandla axoshayo phakathi kwama-nuclei ukuthi alinganiswe ngokukhangana kwama-electron-nucleus, ngaleyo ndlela kuzinziswe uhlelo.

Isibopho se-covalent esingeyona i-polar , esibizwa nangokuthi isibopho se-covalent esimsulwa noma esi-apolar, siwukuhlangana kwama-athomu amabili abelana ngepheya elilodwa noma ngaphezulu lama-electron cishe ngokulinganayo . Okusho ukuthi, ama-electron akha isibopho achitha cishe isikhathi esifanayo eduze kwelinye lama-athomu njengelinye, ngaphandle kokuhlukaniswa okuphawulekayo kweshaja.

Lolu hlobo lwesibopho lwenzeka phakathi kwama-athomu amabili afanayo (esici esifanayo) noma phakathi kwama-athomu amabili ahlukene ane -electronegativities ezifanayo kakhulu . Ngokuphathelene nomehluko we-electronegativity, isibopho se-covalent sibhekwa njenge-nonpolar uma lo mehluko uphakathi kuka -0 no-0,4–0,5 . Ngaphansi kwala manani, ukusatshalaliswa kwamafu e-electron kulinganiselwe ngokwanele kangangokuthi azikho izigxobo ezichazwe ngokucacile.

Ama-molecule avela kulolu hlobo lwesibopho awanayo i-net charge futhi avame ukulingana ngesakhiwo, okufaka isandla kumzuzu we-dipole ophelele ongu-zero. Akulona uhlobo lwesibopho oluningi kakhulu kuzo zonke izinhlanganisela, kodwa luyisisekelo, isibonelo, kuma-molecule e-diatomic amagesi amaningi kanye nenani elikhulu lezinhlanganisela zezinto eziphilayo.

Izinhlobo zezibopho ze-covalent ezingezona i-polar ngokusho kwama-electron abiwe

Esibophweni esingenabo ubumbano, ama-athomu angabelana ngama-electron amabili, amabili, noma amathathu . Kuye ngokuthi zingaki izibhangqwana ezabiwe, izinhlobo eziningana ziyahlukaniswa:

• Isixhumanisi esilula: kuyabiwa imbhangqwana eyodwa kwama-electron phakathi kwama-athomu amabili. Lokhu kunjalo ngesibopho se-H-H ku-molecule ye-hydrogen (H2).
• Isixhumanisi esikabili: zabelwana ngazo amabhangqa amabili ama-electron. Isibonelo yisibopho se-C=C ku-molecule ye-ethylene (C2H4), lapho ama-electron abiwe esatshalaliswa cishe ngokulinganayo phakathi kwama-carbon womabili.
• Isixhumanisi esiphindwe kathathu: zabelwana ngazo amapheya amathathu ama-electron. Isibonelo esijwayelekile yisibopho se-N≡N ku-molecule ye-nitrogen (N2), okuthi, naphezu kwamandla ayo amakhulu, isalokhu iyisibopho esingenabo ubunye ngenxa yokulingana kwama-electronegativities.

Kuzo zonke lezi zimo, isici esinqumayo akusikho nje inani lama-pair abiwe, kodwa ukulingana noma ukufana kwe-electronegativity yama-athomu ahlanganyelayo, okuyikho okuqinisekisa ukungabikho kwezigxobo eziphawuliwe.

Izibonelo zezibopho ze-covalent ezingezona epolar

Kunezibonelo eziningi zezibopho ze-covalent ezingezona ezi-polar, kokubili kuma-molecule akhiwe ngama-athomu afanayo nakulawo akhiwe ngama-athomu ahlukene ane-electronegativities efanayo. Ezinye zezimo ezimele kakhulu yilezi ezilandelayo:

• Izibopho phakathi kwama-athomu afanayo: lapho kwakheka isibopho phakathi kwama-athomu amabili e- into efanayoUmehluko ku-electronegativity u-zero ngqo. Ifu le-electron labelwana ngokulinganayo phakathi kokubili. Izibonelo zakudala yi-hydrogen (H₂) kanye ne-hydrogen (H₂).2), i-nitrogen (N2), umoya-mpilo (O2), i-fluorine (F2), i-bromine (Br2) kanye namanye ama-molecule e-diatomic ezinto ezingezona ezensimbi.
• I-molecule ye-hydrogen (H)2): Ama-athomu amabili e-hydrogen abelana nge-electron yawo eyodwa ye-valence ukuze akhe isibopho esisodwa se-covalent. Njengoba womabili ama-athomu efana, umehluko we-electronegativity ungu-zero, ngakho-ke isibopho sisobala. i-nonpolar.
• I-molecule ye-fluorine (F)2Nakuba i-fluorine iyisici esingesona esi-electronegative kakhulu etafuleni le-periodic, lapho i-athomu eyodwa ye-fluorine ibophana nenye, ayikho engadonsela ifu le-electron ngamandla kakhulu kunenye. I-electronegativity iyafana, futhi isibopho asiyona i-covalent e-polar.
• I-molecule ye-ozone (O2)3Kule molekyuli, i-athomu ephakathi ye-oxygen ixhunyaniswa namanye ama-athomu amabili e-oxygen ngezibopho ze-covalent. Izibopho ze-OO, ngazinye, i-covalent engeyona i-polar ngoba zenzeka phakathi kwama-athomu ane-electronegativity efanayo, yize i-molecule ephelele inesakhiwo esiyinkimbinkimbi kakhulu kanye nemiphumela ethile ye-resonance.
• I-molecule ye-nitrogen (N)2): i-athomu ngayinye ye-nitrogen ihlanganyela ama-electron ayo amathathu e-valence angabhangqiwe nenye, yakha i- isixhumanisi esiphindwe kathathuUmehluko ku-electronegativity ungu-zero, ngakho-ke isibopho se-N≡N asiyona i-covalent e-polar futhi siqine kakhulu.
• izibopho ze-CH ku-methane (CH2)4I-Methane iyindaba ethakazelisayo, njengoba izibopho zayo ze-C-H zenzeka phakathi kwama-athomu ezinto ezahlukene. Umehluko we-electronegativity phakathi kwekhabhoni ne-hydrogen useduze kakhulu 0,4Leli nani lisemngceleni phakathi kwesibopho esingeyona i-polar kanye nesibopho esingeyona i-polar kancane. Ezimweni eziningi, kubhekwa njengesibonelo sesibopho esingeyona i-polar covalent, noma okungenani esinye se-polarity ephansi kakhulu. Ngaphezu kwalokho, i- i-geometry ye-tetrahedral Izakhiwo ze-methane zibangela ukuthi, noma ngabe isibopho ngasinye singaba ne-polarity encane, izikhathi ze-dipole ziyahlukana bese yonke i-molecule ayiyona i-polar.
• I-molecule ye-ethylene (C)2H4): i-ethylene inezibopho ezine ze-CH kanye nenye C=C isibopho esiphindwe kabiliZombili izibopho ze-CH (ze-polarity ephansi kakhulu) kanye nesibopho se-C=C ziyizibopho ze-covalent ezingezona i-polar maqondana nokusatshalaliswa kweshaja. I-molecule iyonke ibonisa ukulingana okuqinisa uhlamvu lwayo olungezona i-polar.
• I-carbon sulfide (CS)2): le nhlanganisela ine-athomu yekhabhoni ehlanganiswe ngokuqondile nama-athomu amabili esibabule ngokusebenzisa izibopho eziphindwe kabili C=S. Umehluko ku-electronegativity phakathi kwekhabhoni nesulfure awumkhulu kakhulu, ngakho-ke amabhondi anophawu oluphansi oluphansi. Ngaphezu kwalokho, i-geometry eqondile ibangela ukuthi noma yiziphi izikhathi ze-dipole ezingaba khona zihlukane, okuholela ku-molecule engeyona i-polar iyonke.

Kuzo zonke lezi zibonelo, ama-electronegativities ayalingana, noma umehluko ungaphansi kuka -0,4 – 0,5 , okuqinisekisa ukusatshalaliswa okufanayo kwefu lama-electron ahlanganyelwe.

Izici zamakhemikhali anezibopho ze-nonpolar covalent

Ama-compound akhiwe ngokuyinhloko ngama-nonpolar covalent bonds abonisa isethi yezimpawu eziwahlukanisa kuma-ionic compounds noma lawo ane-polar covalent bonds eqinile. Phakathi kwezimpawu zawo ezibaluleke kakhulu yilezi ezilandelayo:

• Zinezinga eliphansi lokuncibilika nokubila uma kuqhathaniswa namakhemikhali e-ionic noma ensimbi. Izinto eziningi zalolu hlobo zisesimweni segesi noma soketshezi ekushiseni kwegumbi, njenge-hydrogen (H₂).2), i-nitrogen (N)2noma i-bromine (Br2).
• Azihambisi kahle ukushisangoba azinawo ama-electron amahhala noma ama-ion ahambayo angathutha amandla okushisa ngendlela ephumelelayo esakhiweni.
• wakhe okungancibiliki emanzini emazingeni okushisa ahlukahlukene, noma abonisa ukuncibilika okuphansi kakhulu. Njengomthetho ojwayelekile, ama-compounds okungeyona i-polar Avame ukuncibilika kangcono ezincibilikisini ezingezona ezipholi (njengama-hydrocarbon athile), kuyilapho amanzi eyincibilikisini enamandla epholi.
• wakhe ama-conductor kagesi angasebenzi kahleNjengoba ama-molecule awo engathathi hlangothi ngogesi futhi awahlukani abe ama-ion lapho encibilika, futhi azikho izithwali zokushaja ezihambayo, ugesi awudluliswa kalula.
• Ama-molecule ngokuvamile i-symmetrical maqondana nendiza yokubhekisela noma i-axis, okufaka isandla ekutheni isamba se-vector sezikhathi ze-bond dipole ezingaba khona sibe yi-zero. Lokhu kulinganisa kuyisihluthulelo sokuthi i-compound iziphathe njengento engeyona i-polar iyonke.
• Yethula amandla okubopha aphansi kakhulu Uma kuqhathaniswa nezinye izibopho ze-ionic noma amanethiwekhi amakhulu e-covalent (njengedayimane), lokhu kusho ukuthi, ngokuvamile, kudingeka amandla amancane ukuze kuphulwe isibopho se-covalent esingeyona i-polar kunokuphula isibopho esinamandla se-ionic.
• Bangakha izinto eziqinile, uketshezi, noma amagesi ekushiseni kwegumbi, kuye ngamandla amandla aphakathi kwama-molecule (amandla okusabalala kweLondon, i-dipole ebangelwe, njll.) kanye nosayizi wama-molecule. Isibonelo, i-nitrogen (N)2) iyigesi, i-bromine (Br2) iyizinto eziwuketshezi kanye nezinto eziphilayo ezifana ne-naphthalene (C10H8) ziyizinto eziqinile zama-molecule.

Uma zihlanganiswa, lezi zakhiwo zichaza ukuthi kungani ama-compound amaningi anezibopho ze-covalent ezingezona ezi-polar esetshenziswa njengezinto zokuxazulula izinto eziphilayo , amafutha, noma izinto zokuvikela, kokubili kagesi kanye nokushisa.

Inqubo yokukhomba uhlobo lwesibopho ku-molecule

Uma ufisa ukuhlonza ngokunembile ukuthi uhlobo lwesibopho ku-molecule aluyona i-covalent e-polar , ungalandela inqubo elula esekelwe ku-electronegativity yezinto:

• Okokuqala, thola ukuthi yiziphi izakhi ezakha i-molecule kanye nohlobo lwazo: ukuthi ngabe ziyi- izinsimbiNgokuvamile zitholakala ohlangothini lwesobunxele naphakathi kwethebula le-periodic; uma zikhona okungezona izinsimbi, zitholakala ohlangothini lwesokudla (kufaka phakathi i-hydrogen ezinhlelweni eziningi zokutadisha).
• Ngaphambi kokubala, usuvele unayo eyodwa umqondo womphumelaNgokwencazelo, uma ukhona lapho kukhona izinto ezimbili ezingezona ezensimbi, kuzokwakheka inhlanganisela. isibopho esivumelanayoUmbuzo uzohlala ukhona ukuthi ngabe kuzoba yi-polar noma cha.
• Thola i- ugesi kwento ngayinye kuthebula le-periodic (ngokuvamile kusetshenziswa amanani esikali se-Pauling). Bhala phansi inani elihambisana ne-athomu ngayinye ehlanganyela ku-bond.
• Yenza ifayili le- ukususa okulula phakathi kwamanani e-electronegativity ​​(ngokuvamile, inani eliphakeme lisuswe inani eliphansi). Umphumela uzokunikeza umehluko we-electronegativity phakathi kwama-athomu womabili.
• Qhathanisa inani elitholiwe nezikhawu zokubhekisela: uma umehluko uwukuthi okukhulu noma okulingana no-1,7, isibopho sizoba yi-ionic kakhulu; uma siphakathi I-0,5 ne-1,7, kuyacatshangelwa i-polar covalentFuthi uma kunjalo ngaphansi noma okulingana no-0,4 – 0,5, Kumayelana ne- isibopho se-covalent esingeyona i-polar noma i-polarity ephansi kakhulu.

Ngaphezu kwalokhu kuhlaziywa kwenani, kubalulekile ukucabangela i -geometry ye-molecule . I-molecule ingaqukatha izibopho eziningana ze-polar kodwa ingabi yi-polar emhlabeni wonke uma ukuhlelwa kwendawo kwezibopho kubangela ukuthi izikhathi ze-dipole zihlukane. Isibonelo esijwayelekile yi-carbon dioxide (CO₂ ) , lapho izibopho ze-C=O zi-polar, kodwa i-geometry eqondile yenza i-total dipole moment zero.

Ukuqonda i-bond polarity kanye ne-molecular polarity kubalulekile ku-chemistry ukubikezela izakhiwo ezifana nokuncibilika, amaphuzu okuncibilika nokubila, ukusabela, kanye nokuziphatha kwezinto ezisetshenziswayo ezindabeni ezahlukene.

Ucwaningo oluningiliziwe lwezibopho ze-covalent ezingezona e-polar lusenza siqonde ukuthi kungani izinto eziningi zansuku zonke (amagesi asemkhathini, amafutha, amapulasitiki kanye namanye ama-molecule e-organic) zibonisa ukuziphatha okuhlukile kakhulu kulokho kosawoti we-ionic noma izinsimbi, naphezu kokuba zakhiwe ngezinhlobo ezimbalwa zama-athomu ahlangana ngezindlela ezahlukene.