Ob lub tshuaj lom neeg sib txuas raws li cov tshuaj lom neeg tau tsim los ntawm cov lwg me me, thiab cov no yog ua los ntawm atoms. Cov atoms tseem koom ua ke ua tsaug rau kev tsim cov npe tshuaj txuas.
Cov tshuaj lom neeg tsis zoo ib yam: hauv paus lawv nyob ntawm cov yam ntxwv hluav taws xob ntawm cov atoms koom nrog. Muaj ob hom kev sib txuas feem ntau: ionic daim ntawv cog lus thiab cov covalent bonds.
Feem ntau, covalent bonds yog cov uas tuav cov hlau tsis yog xim hlau ua ke. Nws tshwm sim tias cov atoms ntawm cov ntsiab lus no muaj ntau lub tshuab hluav taws xob hauv lawv lub plhaub sab nrauv thiab muaj lub siab nyiam khaws cia lossis nce hluav taws xob, tsis txhob muab lawv tso rau.
Tias yog vim li cas txoj hauv kev uas cov tshuaj no lossis cov tshuaj sib xyawicos ua tiav kev ruaj ntseg yog los ntawm kev sib koom ib khub ntawm cov khoom siv hluav taws xob, utsis yog los ntawm txhua lub atom. Qhov no txoj kev sib koom ua ke ntawm cov khoom siv hluav taws xob tau tshwm sim rau ob lub atoms thiab tib lub sijhawm tuav lawv ua ke. Hauv cov nkev nom tswv, piv txwv li, qhov no tshwm sim. Tsis tas li hauv cov ntsiab lus halogen.
Thaum covalent daim ntawv cog lus tshwm sim ntawm cov ntsiab lus zoo sib xws electronegativity, xws li nruab nrab ntawm hydrogen thiab carbon, cov nyiaj tau los apolar covalent. Qhov no tshwm sim, piv txwv li, hauv hydrocarbons.
Ib yam nkaus, homonuclear molecules (ua los ntawm tib lub atom) ib txwm tsim daim ntawv cog lus apolar. Tab sis yog tias kev sib koom ua ke tshwm sim ntawm cov ntsiab lus sib txawv ntawm electronegativity, lub zog hluav taws xob ntau dua tau tsim hauv ib qho atom dua li lwm qhov, vim qhov no tau tsim ib tus ncej.
Qhov thib peb muaj peev xwm yog tias ob lub atoms sib koom ua ke ntawm cov hluav taws xob, tab sis cov kev sib koom ua ke no tau pab los ntawm ib qho ntawm lawv xwb. Hauv qhov no peb tham txog dative lossis koom tes covalent daim ntawv cog lus.
Rau a dative txuas koj xav tau lub hauv paus nrog cov khoom siv hluav taws xob dawb (zoo li nitrogen) thiab lwm qhov uas tsis muaj hluav taws xob (xws li hydrogen). Nws kuj tseem tsim nyog tias ib qho nrog cov khoom siv hluav taws xob yog hluav taws xob txaus kom tsis txhob poob cov hluav taws xob los sib qhia. Qhov xwm txheej no tshwm sim, piv txwv li, hauv ammonia (NH4+).
Cov tshuaj muaj covalent sib txuas tuaj yeem tshwm sim hauv txhua lub xeev qhov teeb meem (khoom, kua lossis roj cua), thiab feem ntau lawv yog cov neeg ua haujlwm tsis zoo ntawm cov cua sov thiab hluav taws xob.
Lawv nquag qhia kuj tsis tshua muaj melting thiab cov ntsiab lus kub thiab feem ntau yog soluble hauv cov kuab tshuaj polar, zoo li benzene lossis carbon tetrachloride, tab sis muaj cov dej tsis haum hauv dej. Lawv ruaj khov heev.
Ntau qhov piv txwv ntawm cov sib txuas lossis cov tshuaj uas muaj covalent bonds tuaj yeem muab tau:
- Tshuaj fluorine
- Bromine
- Iodine
- Tshuaj
- Cov pa
- Dej
- Cov pa roj carbon dioxide
- Ammonia
- Methane
- Propane
- Silica
- Pob zeb diamond
- Graphite
- Quartz
- Ntshav qab zib
- Paraffin
- Diesel
- Nitrogen
- Helium
- Freon
