Qhov sib txawv tseem ceeb ntawm txoj kev xav molecular orbital thiab hybridization txoj kev xav yog qhov kev tshawb xav molecular orbital piav qhia txog kev tsim cov kev sib txuas thiab kev sib txuas lus los tiv thaiv kev sib txuas, qhov hybridization txoj kev xav piav qhia txog kev tsim cov hybrid orbitals.
Muaj ntau qhov kev xav tau tsim los txiav txim siab cov qauv hluav taws xob thiab orbital ntawm cov molecules. VSEPR txoj kev xav, Lewis txoj kev xav, valence bond theory, hybridization theory thiab molecular orbital theory yog cov kev xav tseem ceeb. Qhov kev xav tau tshaj plaws ntawm lawv yog txoj kev xav molecular orbital.
Dab tsi yog Molecular Orbital Theory?
Molecular orbital theory yog ib qho txheej txheem ntawm kev piav qhia cov qauv hluav taws xob ntawm cov khoom siv hluav taws xob siv quantum mechanics. Nws yog qhov tsim nyog tshaj plaws ntawm kev piav qhia txog kev sib txuas ntawm cov tshuaj hauv cov molecules. Cia peb tham txog qhov kev xav no kom ntxaws.
Ua ntej, peb yuav tsum paub tias molecular orbitals yog dab tsi. Ib daim ntawv cog lus tshuaj tsim los ntawm ob lub atoms thaum lub zog txaus nyiam ntawm ob lub atomic nuclei thiab cov electrons nyob nruab nrab ntawm lawv tshaj qhov electrostatic repulsion ntawm ob lub atomic nuclei. Qhov tseeb, qhov no txhais tau tias, lub zog txaus nyiam ntawm ob lub atom yuav tsum siab dua li lub zog quab yuam ntawm ob lub atom. Ntawm no, cov electrons yuav tsum muaj nyob rau hauv ib cheeb tsam hu ua "binding region", los tsim no chemical bond. Yog tias tsis yog, cov hluav taws xob yuav nyob rau hauv "thaj tsam tiv thaiv" uas yuav pab txhawb lub zog ntawm cov atoms.
Txawm li cas los xij, yog tias cov kev xav tau ua tiav thiab cov ntawv cog lus tshuaj lom neeg ntawm ob lub atom, ces cov khoom sib txuas uas cuam tshuam nrog kev sib txuas yog hu ua molecular orbitals. Ntawm no, peb tuaj yeem pib nrog ob lub orbitals ntawm ob lub atoms thiab xaus nrog ib lub orbital (lub molecular orbital) uas belongs rau ob lub atoms.
Raws li quantum mechanics, atomic orbitals tsis tuaj yeem tshwm sim lossis ploj mus raws li peb xav tau. Thaum orbitals cuam tshuam nrog ib leeg, lawv nyiam hloov lawv cov duab raws li. Tab sis raws li quantum mechanics, lawv muaj kev ywj pheej los hloov cov duab tab sis yuav tsum muaj tib lub orbitals. Tom qab ntawd peb yuav tsum nrhiav lub orbital uas ploj lawm. Ntawm no, nyob rau hauv-theem ua ke ntawm ob lub atomic orbitals ua rau lub tsev cog khoom orbital thaum tawm-ntawm-theem ua ke ua rau cov anti-bonding orbital.
Daim duab 01: Molecular Orbital Diagram
Cov khoom siv hluav taws xob nyob hauv lub tsev cog khoom orbital thaum cov hluav taws xob hauv kev tiv thaiv kev sib txuas lus tsis koom nrog kev tsim cov ntawv cog lus. Es tsis txhob, cov electrons nquag tawm tsam kev tsim cov tshuaj lom neeg daim ntawv cog lus. Lub tsev cog khoom orbital muaj peev xwm qis dua lub zog tiv thaiv kev sib txuas. Yog hais tias peb xav txog ib daim ntawv cog lus sigma, lub denotation rau bonding orbital yog σ, thiab lub anti-bonding orbital yog σ. Peb tuaj yeem siv txoj kev xav no los piav txog cov qauv ntawm cov molecules nyuaj los piav qhia vim li cas qee cov molecules tsis muaj (piv txwv li He 2) thiab cov nyiaj txiav txim ntawm cov molecules. Yog li, qhov kev piav qhia luv luv piav qhia lub hauv paus ntawm molecular orbital txoj kev xav.
Hybridization Theory yog dab tsi?
Hybridization txoj kev xav yog ib qho txheej txheem uas peb siv los piav txog cov qauv orbital ntawm lub molecule. Hybridization yog tsim ntawm hybrid orbitals los ntawm kev sib tov ob los yog ntau tshaj atomic orbitals. Qhov kev taw qhia ntawm cov orbitals no txiav txim siab qhov geometry ntawm cov molecule. Nws yog kev nthuav dav ntawm valence bond theory.
Ua ntej tsim cov atomic orbitals, lawv muaj lub zog sib txawv, tab sis tom qab tsim, tag nrho cov orbitals muaj tib lub zog. Piv txwv li, ib qho atomic orbital, thiab p atomic orbital tuaj yeem ua ke los ua ob lub sp orbitals. Lub s thiab p atomic orbitals muaj lub zog sib txawv (lub zog ntawm s < lub zog ntawm p). Tab sis tom qab hybridization, nws tsim ob sp orbitals uas muaj tib lub zog, thiab lub zog no nyob nruab nrab ntawm lub zog ntawm tus kheej thiab p atomic orbital energies. Ntxiv mus, qhov no sp hybrid orbital muaj 50% s orbital yam ntxwv thiab 50% p orbital yam ntxwv.
Daim duab 02: Daim ntawv cog lus ntawm Hybrid Orbitals ntawm Carbon Atom thiab s Orbitals ntawm Hydrogen Atoms
Lub tswv yim ntawm kev sib xyaw ua ntej nkag mus rau hauv kev sib tham vim tias cov kws tshawb fawb pom tias txoj kev xav ntawm valence bond ua tsis tau raws li kev kwv yees tus qauv ntawm qee cov molecules xws li CH4Ntawm no, txawm hais tias cov pa roj carbon atom tsuas muaj ob lub tshuab hluav taws xob tsis sib xws raws li nws cov khoom siv hluav taws xob, nws tuaj yeem tsim plaub daim ntawv cog lus. Txhawm rau tsim plaub daim ntawv cog lus, yuav tsum muaj plaub lub tshuab hluav taws xob tsis sib xws.
Tib txoj kev uas lawv tuaj yeem piav qhia qhov tshwm sim no yog xav tias s thiab p orbitals ntawm carbon atom fuse nrog ib leeg los tsim cov orbitals tshiab hu ua hybrid orbitals uas muaj tib lub zog. Ntawm no, ib tug s + peb p muab 4 sp3 orbitals. Yog li ntawd, cov electrons sau cov hybrid orbitals tusyees (ib tug electron ib hybrid orbital), ua raws li Hund txoj cai. Tom qab ntawd muaj plaub lub electrons rau tsim plaub covalent bonds nrog plaub hydrogen atoms.
Qhov txawv ntawm Molecular Orbital Theory thiab Hybridization Theory yog dab tsi?
Txoj kev xav molecular orbital yog ib qho txheej txheem ntawm kev piav qhia cov qauv hluav taws xob ntawm cov khoom siv hluav taws xob siv quantum mechanics. Hybridization txoj kev xav yog ib qho txheej txheem uas peb siv los piav txog cov qauv orbital ntawm lub molecule. Yog li, qhov sib txawv tseem ceeb ntawm molecular orbital txoj kev xav thiab hybridization txoj kev xav yog tias molecular orbital txoj kev xav piav qhia txog kev tsim kev sib raug zoo thiab kev tiv thaiv kev sib khi orbitals, whereas hybridization txoj kev xav piav qhia txog kev tsim cov hybrid orbitals.
Tsis tas li ntawd, raws li txoj kev xav molecular orbital, cov ntaub ntawv tshiab orbital los ntawm kev sib xyaw ntawm atomic orbitals ntawm ob lub atoms thaum nyob rau hauv hybridization txoj kev xav, cov ntaub ntawv tshiab orbital tsim qhov sib xyaw ntawm atomic orbitals ntawm tib lub atom. Yog li, qhov no yog lwm qhov sib txawv ntawm molecular orbital theory thiab hybridization theory.
Summary – Molecular Orbital Theory vs Hybridization Theory
Ob txoj kev tshawb xav molecular orbital thiab hybridization txoj kev xav yog qhov tseem ceeb hauv kev txiav txim siab cov qauv ntawm cov molecule. Qhov sib txawv tseem ceeb ntawm molecular orbital txoj kev xav thiab hybridization txoj kev xav yog tias molecular orbital txoj kev xav piav qhia txog kev tsim kev sib raug zoo thiab kev tiv thaiv kev sib khi orbitals, whereas hybridization txoj kev xav piav qhia txog kev tsim cov hybrid orbitals.
