Lub ntsiab yam tshuaj bonds: yog vim li cas thiab yuav ua li cas lawv raug tsim

Kev cai lij choj uas ua lub tshuaj rau ib ntev lub sij hawm tseem ib unsolved paub tsis meej rau tus txiv neej. Lub classical kev tshawb xav ntawm atomic bonds twb muaj heev lig - nyob rau hauv 1916. Txij thaum ntawd los, zaum lub tswv yim tau hloov zuj zuj. Nyob rau hauv hauv paus ntsiab lus, tsis muaj dab tsi tshiab txij thaum ntawd los twb tsis qhib, thiab lub hom tshuaj bonds tam sim no paub txhua tus menyuam kawm ntawv, uas tsawg kawg yog nws mus kawm. Rau txoj kev paub no ib co ntawm cov medieval zaum tau muag lawv tej ntsuj plig.

Yog li ntawd, muaj lub ntsiab hom tshuaj bonds thiab ib qho ntxiv hu ua tsis muaj zog cov kev sib tshuam. Tej zaum lawv txawm li cas los, ua ib qho tseem ceeb, e.g., nyob rau hauv lub tsim ntawm cov protein qauv. Lub ntsiab yam ntawm tshuaj bonds muaj xws li covalent thiab ionic thiab txawm hlau.

Peb pib nrog covalent. Nws yog rau lawv Gilbert Lewis thiab muaj nws thawj classical kev tshawb xav ntawm cov tshuaj daim ntawv cog lus. Yuav ua li cas yog lub tswv yim hais tias tus paub txog tseem tshuaj pleev? Lub covalent daim ntawv cog lus yog tsim vim hais tias nyob rau hauv bound daim ntawv nyob rau hauv lub system ntawm atoms yog tau tsawg zog dua singly atoms. Thiab qhov no yog ib qho tseem ceeb nyob rau hauv Science News for KIDS. Txhua system aims kom tshem tau ntawm lub siab tshaj plaws nqi zog. Thaum lub sij hawm tsim ntawm lub covalent daim ntawv cog lus, txhua txhua tus sib txuas atoms txhawb rau cov creation ntawm lub kev twb kev txuas. Yog li, ib tug sab nraud hluav taws xob theem yog lawm ua tus sau, tus hais nrog ib tug tsis zoo xwb dhau "nyob rau hauv kev pab."

Hom tshuaj bonds yog muab faib ua subtypes. Piv txwv li, ib tug covalent daim ntawv cog lus feem ntau yog tsis yog-polar - xws li, nruab nrab ntawm atoms ntawm ib yam tshuaj uas caij. Yog li tsim roj molecules xws li nitrogen, fluorine, hydrogen. Electron khub "ntau cov tswv cuab" yog geometrically ib ncig ntawm lub nruab nrab. Txawm hais tias nws yog ib qhov nyuaj rau hais tias, vim hais tias cov kev tshawb fawb tau qhia tias cov electron txoj kev yog yuav luag tsis yooj yim sua twv seb.

Lwm yam - txoj kev sib khi ntawm lub atoms ntawm txawv tshuaj ntsiab. Piv txwv li, nyob rau hauv kev twb kev txuas ntawm lub fluorine thiab hydrogen atoms ntau chav yog spatially los ze zog mus rau ib lub atoms, namely - mus fluorine. Qhov no kev sib raug zoo yog lub ncov qaumteb qabteb lub npe.

Tab sis atoms yog tsis ib txwm "ncaj ncees pab sib npaug rau" lub tsim ntawm lub deposit. Nws kuj tshwm sim hais tias ib tug ntawm cov atoms ncaj qha muab ob electrons, thiab lub thib ob - orbit rau cov uas khub uas kis tau mus rau hauv kev siv. Yuav ua li cas mus rau npe rau qhov xwm ntawm no kev twb kev txuas? Donor-acceptor hom kev sib txuas lus. Lub ammonium ion yuav tau ib tug zoo piv txwv. Peb hydrogen atoms yog muab kev koom tes nyob rau hauv cov pa ncov qaumteb qabteb covalent bonds, thiab tshuav free khub ntawm electrons ntawm nitrogen tej zaum yuav kis tau rau hauv sib koom siv nrog lwm tus hydrogen atom. Tseem, xws li ib tug txuas yog ib tug covalent, vim hais tias cov chaw uas muaj zog electron ceev ntawm lub atoms yog.

Yuav ua li cas lwm hom tshuaj bonds muaj nyob? Ionic daim ntawv cog lus tshwm sim ntawm hais muaj ib tug txawv xwb. Lub quab yuam ntawm attraction ntsiab ntawm kev sib raug zoo nyob tsuas yog nyob rau qhov kev ncua deb uas cais lawv, thiab nyob rau hauv orientation - ywj siab. Qhov twg muaj xws li kev mus? Ua ntej ntawm tag nrho cov, nyob rau hauv crystalline cov ntaub ntawv - alkalis, carbides, ntsev, nitrides, yooj yim oxides. Yog hais tias lub ntawv thiab anion yog zoo xws li cov nyob rau hauv loj, lub kev twb kev txuas yog tshwj xeeb yog ruaj khov. Ib txhia chemists yuav mus xav seb qhov no zoo ntawm kev twb kev txuas ib huab ntaub ntawv ntawm ib tug dawb covalent daim ntawv cog lus. Tab sis nws yog ib tug moot point, vim hais tias cov electron ceev yog tseem tsis heev nyob ze rau qhov tsis zoo them ntawv.

Lub nws yog xim hlau daim ntawv cog lus no feem ntau yog npaum li cas txawv los ntawm lwm hom tshuaj bonds. Txij li thaum nws tsis yog tsuas yog cim sib tab sis lub cev peculiar phenomenon. Qhov tseeb hais tias nyob rau hauv lub tsim ntawm electrons koom kev sib txuas lus atoms. Thiab lawv directional zog piav tau mas conductive hluav taws xob tam sim no nyob rau hauv cov hlau. Li ntawd, txhua atom nyob rau hauv lub ntxaij ntoo site muaj txhawb rau daim ntawv cog lus.

Raws li tau muaj tseeb ntawm qhov kev piav qhia saum toj no, lub hom tshuaj bonds yog distinguished precisely los ntawm lub hauv paus ntsiab lus ntawm lawv tsim.