Qhov sib txawv tseem ceeb ntawm ob daim ntawv cog lus thiab ib daim ntawv cog lus yog tias, nyob rau hauv ib qho kev sib cog lus, ob lub atoms sib koom ib qho hluav taws xob ua ke tsuas yog nyob nruab nrab ntawm qhov chaw, hauv ob daim ntawv cog lus, ob lub atoms faib ob lub electron..
Raws li tau hais los ntawm American chemist G. N. Lewis, atoms ruaj khov thaum lawv muaj yim electrons hauv lawv lub plhaub valence. Feem ntau ntawm cov atoms muaj tsawg tshaj li yim electrons nyob rau hauv lawv valence shells (tshwj tsis yog cov noble gases nyob rau hauv pab pawg neeg 18 ntawm lub periodic rooj); yog li ntawd, lawv tsis ruaj khov. Cov atoms no zoo li ua rau ib leeg, ua kom ruaj khov. Yog li, txhua lub atom tuaj yeem ua tiav cov roj hluav taws xob hluav taws xob zoo. Thiab, qhov no tuaj yeem tshwm sim los ntawm kev tsim cov ionic bonds, covalent bonds lossis metallic bonds. Ntawm cov no, covalent bonding yog tshwj xeeb. Ib daim ntawv cog lus ib leeg thiab ob daim ntawv cog lus tuaj nyob rau hauv qeb ntawm daim ntawv cog lus.
Dub Bond yog dab tsi?
Ob daim ntawv cog lus thaum ob lub atoms sib koom ob khub ntawm cov hluav taws xob nruab nrab ntawm lawv kom sau cov valence orbitals. Ob daim ntawv cog lus luv dua li ib daim ntawv cog lus tab sis muaj zog dua lawv. Sp2 hybridization tso cai rau cov atoms tsim ob daim ntawv cog lus.
Ob daim ntawv cog lus tuaj yeem yog ob hom. Ntawm ob daim ntawv cog lus, ib qho yog sigma daim ntawv cog lus. Nws tsim los ntawm cov kab sib tshooj ntawm ob sp2 hybridized orbitals. Thib ob, lwm daim ntawv cog lus (uas peb lub npe hu ua pi daim ntawv cog lus) tsim los ntawm kev sib tshooj ntawm ob sab orbitals.
Daim duab 01: Muab ob npaug rau xim liab
Qhov piv txwv ntawm ib lub molecule nrog ob daim ntawv cog lus yog ethylene. Hauv ethylene, ob daim ntawv cog lus yog nruab nrab ntawm ob lub atoms carbon. Txawm li cas los xij, tsis yog ntawm cov atoms zoo sib xws, hom kev sib txuas no tuaj yeem tsim ntawm cov atoms sib txawv ib yam li hauv cov piv txwv ntawm carbonyl carbon (C=O), imines (C=N), azo compounds (N=N) thiab lwm yam.
Dab tsi yog Ib Daim Ntawv Pov Thawj?
Ib daim ntawv cog lus ib zaug thaum ob lub atoms uas zoo sib xws lossis qis electronegativity sib txawv sib koom ib khub ntawm electrons. Ob lub atom no tuaj yeem yog tib hom lossis ntau hom. Piv txwv li, thaum tib hom atoms koom ua cov molecules xws li Cl2, H2, los yog P4, txhua lub atom khi nrog lwm tus los ntawm ib daim ntawv cog lus.
Methane molecule (CH 4) muaj ib qho kev sib cog lus ntawm ob hom khoom (carbon thiab hydrogen atoms). Tsis tas li ntawd, methane yog ib qho piv txwv rau lub molecule uas muaj covalent bonds ntawm atoms uas tsis tshua muaj electronegativity sib txawv.
Daim duab 02: Cov qauv ntawm Methane Molecule
Peb lub npe ib daim ntawv cog lus ib leeg kuj yog sigma daim ntawv cog lus. Ib daim ntawv cog lus muab ib lub molecule lub peev xwm mus rau kev sib hloov nyob ib ncig ntawm qhov kev sib cog lus hais txog ib leeg. Yog li ntawd, qhov kev sib hloov no tso cai rau lub molecule kom muaj cov qauv sib txawv. Tsis tas li ntawd, hom ntawv cog lus no ua nrog sp 3 hybridized atoms ntawm ib lub molecule. Thaum ob qhov sib npaug sp3 hybridized molecules linearly overlap, ib daim ntawv cog lus.
Qhov txawv ntawm Ob Daim Ntawv Pov Thawj thiab Ib Daim Ntawv Pov Thawj yog dab tsi?
Covalent daim ntawv cog lus feem ntau yog peb hom; ib daim ntawv cog lus, ob daim ntawv cog lus, thiab triple daim ntawv cog lus. Qhov sib txawv tseem ceeb ntawm ob daim ntawv cog lus thiab ib daim ntawv cog lus yog tias, hauv ib daim ntawv cog lus nkaus xwb, tsuas yog ib khub hluav taws xob sib koom ntawm ob lub atoms thaum, hauv kev tsim ob daim ntawv cog lus, ob lub electron sib koom.
Ntxiv mus, qhov sib txawv tseem ceeb ntawm ob daim ntawv cog lus thiab ib daim ntawv cog lus yog qhov kev sib koom ua ke los ntawm kev sib tshooj ntawm ob sp3 hybridized orbitals thaum ob daim ntawv cog lus los ntawm kev sib tshooj ntawm ob sp2 hybridized orbitals thiab los ntawm lateral overlapping ntawm p orbital.
Sib nrug ntawm qhov ntawd, ib daim ntawv cog lus muaj ib daim ntawv cog lus, thaum ob daim ntawv cog lus muaj ib daim ntawv cog lus thiab ib daim ntawv cog lus. Yog li, qhov no cuam tshuam qhov ntev ntawm cov atoms. Yog li ntawd, ua rau lwm qhov sib txawv ntawm ob daim ntawv cog lus thiab ib daim ntawv cog lus. Qhov ntawd yog; qhov ntev ntawm ib daim ntawv cog lus yog siab dua li ntawm ob daim ntawv cog lus. Ntxiv mus, ob daim ntawv cog lus dissociation zog yog siab dua li ib daim ntawv cog lus dissociation zog.
Summary – Ob Daim Ntawv Pov Thawj vs Ib Daim Ntawv Pov Thawj
Ob daim ntawv cog lus thiab daim ntawv cog lus ib leeg yog hom kev cog lus tshuaj lom neeg. Qhov sib txawv tseem ceeb ntawm ob daim ntawv cog lus thiab ib daim ntawv cog lus yog tias, hauv ib daim ntawv cog lus nkaus xwb, tsuas yog ib qho hluav taws xob sib koom ntawm ob lub atoms thaum, hauv kev tsim ob daim ntawv cog lus, ob qho hluav taws xob sib koom.
