Covalent daim ntawv cog lus

Rau cov thawj lub sij hawm xws li ib tug lub tswv yim raws li ib tug covalent daim ntawv cog lus chemists hais tom qab qhib ntawm Gilbert Newton Lewis, uas piav txog tus daim ntawv cog lus raws li cov socialization ntawm ob electrons. Ntau tsis ntev los no kev tshawb fawb tau piav nws tus kheej covalent daim ntawv cog lus kuj. Cov lo lus tej zaum yuav pom tau tias covalent Science News for KIDS raws li ib feem atom muaj peev xwm tsim tau bonds nrog rau lwm cov atoms.

Ntawm no yog ib qho piv txwv:

Muaj ob atoms nrog me sib txawv nyob rau hauv electronegativity (C thiab CL, C thiab H). Feem ntau, qhov no atoms, cov qauv ntawm cov electron plhaub uas yog structurally ze li sai tau mus rau lub electron plhaub ntawm lub inert gases.

Thaum cov kev mob tshwm sim attraction nuclei ntawm cov atoms mus rau lub electron khub, ntau rau lawv. Nyob rau hauv cov ntaub ntawv no, lub electron huab tsis txhob cia li sib tshooj, raws li nyob rau hauv ionic tsevneeg. Covalent daim ntawv cog lus muab kev ruaj ntseg kev twb kev txuas ntawm ob atoms los ntawm qhov tseeb hais tias lub electron ceev yog rov muaj yais tawm thiab lub zog ntawm lub cev yuav hloov, uas yog tshwm sim los ntawm "retraction" nyob rau hauv qhov chaw internuclear ib electron huab ntawm lwm atom. Qhov ntau uas nws kim heev kev sib nrig sib overlapping ntawm lub electron huab, kev twb kev txuas yog xav tau ntau check.

Li no, lub covalent daim ntawv cog lus - yog kev kawm ntawv, uas sawv los ntawm lub kev sib nrig sib socialization ntawm ob electrons teej tug mus rau ob atoms.

Raws li ib tug txoj cai, cov tshuaj nrog ib tug molecular lattice yog tsim los ntawm ib tug covalent daim ntawv cog lus. Yam ntxwv molecular qauv yog melting thiab boiling thaum uas tsis muaj kub, tsis dej solubility thiab tsawg hluav taws xob conductivity. Li no peb yuav xaus uas lub hauv paus qauv ntawm hais xws li germanium, pob zeb ntais, tshuaj chlorine ua, hydrogen, - ib tug covalent daim ntawv cog lus.

Thaj chaw uas yog raug rau no hom ntawm compound:

1. Kev tsuas xyaus. Nyob rau hauv cov cuab yeej no feem ntau yog to taub raws li lub siab tshaj plaws pes tsawg tus ntawm kev sib txuas uas lawv yuav tsim kom muaj kev atoms. Nws yog txiav txim los ntawm tus nqi ntawm tag nrho cov xov tooj ntawm cov orbitals nyob rau hauv atoms uas tej zaum yuav muab kev koom tes nyob rau hauv lub tsim ntawm cov tshuaj bonds. Lub valency ntawm lub atom, rau lwm cov tes, tej zaum yuav txiav txim los ntawm tus xov tooj ntawm twb siv rau lub hom phiaj no orbitals.
2. Orientation. Tag nrho cov atoms yuav daim ntawv cov lusteb tau daim ntawv cog lus. Maximum zog yog tiav nyob rau hauv cov ntaub ntawv ntawm coincidence ntawm lub spatial orientation ntawm lub electron huab ntawm ob atoms, raws li lawv sib tshooj txhua lwm yam. Nyob rau hauv tas li ntawd, nws yog ib tug covalent daim ntawv cog lus cuab yeej raws li orientation influences lub spatial arrangement ntawm lub lwg me me ntawm cov organic teeb meem, uas yog lub luag hauj lwm rau lawv cov "geometrical zoo".
3. Polarizability. Nyob rau hauv no txoj hauj lwm raws li lub tswv yim hais tias muaj yog ib tug covalent linkage ntawm ob hom:

• ncov qaumteb qabteb los yog uas tsis yog-symmetrical. Kev sib txuas lus ntawm no zoo yuav tsim xwb atoms ntawm ntau hom, i.e. cov neeg uas nws electronegativity txawv muaj nuj nqis, los yog nyob rau hauv tus neeg mob qhov twg tag nrho cov electron khub asymmetrically muab faib.
• nonpolar covalent daim ntawv cog lus tshwm sim ntawm cov pa roj carbon atoms, cov electronegativity uas yog suab sib npaug zos, thiab lub electron ceev faib yog uniform.

Nyob rau hauv tas li ntawd, muaj ntau yam ntau cov yam ntxwv ntawm covalent daim ntawv cog lus:

• Lub losis tswvyim dabtsi zog. Qhov no parameter characterizes lub ncov qaumteb qabteb kev sib raug zoo nyob rau hauv cov nqe lus ntawm nws lub zog. Nyob rau hauv lub zog yog meant tus nqi ntawm tshav kub uas yog yuav tsum tau mus ua txhaum lub kev twb kev txuas ntawm ob atoms, raws li zoo raws li tus nqi ntawm tshav kub uas tau raug faib ntawm lawv hlws ris.
• Nyob rau hauv daim ntawv cog lus lengths thiab molecular Science News for KIDS hais txog qhov ntev ntawm txoj kab ntawm nuclei ntawm ob atoms. Qhov no parameter characterizes lub daim ntawv cog lus lub zog kuj.
• Lub dipole caij - ib tug muaj nuj nqis uas characterizes lub polarity ntawm lub valence daim ntawv cog lus.