Qhov nruab nrab atomic loj tsis yog ntsuas ncaj qha ntawm ib qho atom nkaus xwb. Qhov hnyav no yog qhov nruab nrab qhov nruab nrab ntawm ib qho atom ntawm cov qauv dav dav ntawm cov khoom tshwj xeeb. Yog tias koj tuaj yeem suav qhov hnyav ntawm ib lab lab ntawm ib lub atom, koj tuaj yeem suav qhov txiaj ntsig no ib yam nkaus li koj xav tau lwm qhov nruab nrab. Hmoov zoo, muaj txoj hauv kev yooj yim dua los xam cov atomic loj, uas yog raws cov ntaub ntawv paub los ntawm qhov tsis sib xws ntawm isotopes sib txawv.
Kauj ruam
Ntu 1 ntawm 2: Xam Qhov Nruab Nrab Atomic Mass
Kauj Ruam 1. Nkag siab isotopes thiab atomic masses
Cov ntsiab lus feem ntau tshwm sim ib txwm nyob hauv ntau hom ntawv, hu ua isotopes. Cov lej loj ntawm txhua isotope yog tus naj npawb ntawm protons thiab neutrons hauv nws cov keeb kwm. Txhua lub proton thiab neutron hnyav 1 atomic mass unit (amu). Tsuas yog qhov sib txawv ntawm ob isotopes ntawm ib lub caij yog tus naj npawb ntawm neutrons ib atom, uas cuam tshuam rau atomic loj. Txawm li cas los xij, cov ntsiab lus ib txwm muaj tus lej ntawm protons.
- Qhov nruab nrab atomic loj ntawm ib yam cuam tshuam los ntawm kev hloov pauv ntawm tus lej ntawm nws cov neutrons, thiab sawv cev rau qhov nruab nrab qhov hnyav ib atom hauv cov piv txwv dav dav ntawm cov khoom.
- Piv txwv li, lub hauv paus nyiaj (Ag) muaj 2 qhov tshwm sim ib txwm muaj isotopes, uas yog Ag-107 thiab Ag-109 (lossis). 107Ag thiab 109Ag) Yog. Isotopes muaj npe raws li lawv "tus lej loj" lossis tus naj npawb ntawm protons thiab neutrons hauv ib lub atom. Qhov no txhais tau tias, Ag-109 muaj 2 lub neutron ntau dua li Ag-107 yog li nws qhov hnyav yog me dua.
Kauj Ruam 2. Nco tseg qhov hnyav ntawm txhua isotope
Koj xav tau 2 hom ntaub ntawv rau txhua isotope. Koj tuaj yeem nrhiav cov ntaub ntawv no hauv cov phau ntawv lossis hauv internet xws li webelements.com. Thawj cov ntaub ntawv yog qhov hnyav atomic, lossis qhov hnyav ntawm ib lub atom ntawm txhua isotope. Isotopes uas muaj ntau dua neutrons muaj ntau dua.
- Piv txwv li, cov nyiaj isotope Ag-107 muaj cov atomic loj ntawm 106, 90509 tsev kawm theem siab (atomic pawg tsev). Lub caij no, isotope Ag-109 muaj qhov loj me me, uas yog 108, 90470.
- Ob qhov decimal qhov kawg yuav txawv me ntsis ntawm cov peev txheej. Tsis txhob suav ib tus lej hauv kab ntawv tom qab atomic loj.
Kauj Ruam 3. Sau cov nplua nuj ntawm txhua isotope
Qhov kev nplua nuj no qhia tias muaj isotope ntau npaum li cas feem pua ntawm txhua lub atoms uas tsim los ua ib qho. Txhua isotope yog qhov sib npaug ntawm cov khoom muaj txiaj ntsig (ntau dua qhov muaj ntau ntawm isotope ntau dua qhov cuam tshuam ntawm qhov nruab nrab atomic loj). Koj tuaj yeem pom cov ntaub ntawv no nyob hauv cov peev txheej ib yam li atomic mass. Kev nplua nuj ntawm txhua isotopes yuav tsum yog 100% (txawm hais tias yuav muaj qhov yuam kev me ntsis los ntawm kev ua kom yuam kev).
- Isotope Ag-107 muaj ntau ntawm 51.86%, thaum Ag-109 yog qhov tsawg me ntsis nrog qhov muaj ntau ntawm 48.14%. Qhov no txhais tau tias, cov piv txwv dav dav ntawm cov nyiaj yog suav nrog 51.86% Ag-107 thiab 48.14% Ag-109.
- Tsis quav ntsej ib qho isotopes uas nws qhov kev nplua nuj tsis tau teev tseg. Isotopes zoo li cov no tsis tshwm sim ib txwm nyob hauv ntiaj teb.
Kauj Ruam 4. Hloov qhov feem pua ntawm kev nplua nuj mus rau tus lej lej
Faib qhov feem pua nplua nuj los ntawm 100 kom tau txais tus nqi zoo ib yam hauv zauv zauv.
Nyob rau tib qhov teeb meem, tus lej nplua nuj yog 51.86/100 = 0, 5186 thiab 48, 14/100 = 0, 4814.
Kauj Ruam 5. Nrhiav qhov hnyav nruab nrab atomic loj ntawm isotope ruaj khov
Qhov nruab nrab atomic loj ntawm ib lub caij nrog tus lej isotopes n yog sib npaug rau (pawgisotopes 1 * ntauisotopes 1) + (masisotopes 2 * ntauisotopes 2) +… + (Pawgn isotope ib * ntaun isotope ib . Nov yog qhov piv txwv ntawm "qhov hnyav nruab nrab", uas txhais tau tias, pom ntau qhov (ntau dua qhov muaj ntau) qhov cuam tshuam loj dua rau qhov tshwm sim. Nov yog yuav ua li cas siv cov mis saum toj no rau nyiaj:
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Qhov nruab nrab atomic lojAg = (masLub Yim Hli-107 * ntauLub Yim Hli-107) + (masAW-109 * ntauAW-109)
=(106, 90509 * 0, 5186) + (108, 90470 * 0, 4814)
= 55, 4410 + 52, 4267
= 107, 8677 tsev kawm theem siab.
- Saib ntawm cov ntsiab lus hauv cov ntawv teev sijhawm los tshuaj xyuas koj cov lus teb. Qhov nruab nrab atomic loj feem ntau tau teev tseg hauv qab cov cim cim.
Ntu 2 ntawm 2: Siv Cov Xeem Tau Los
Kauj Ruam 1. Hloov huab hwm coj mus rau tus lej atomic
Qhov nruab nrab atomic loj qhia txog kev sib raug zoo ntawm cov lej thiab cov lej atomic hauv cov piv txwv dav dav ntawm cov khoom. Qhov no muaj txiaj ntsig hauv chav kuaj ntshav vim hais tias suav cov lej atomic ncaj qha yuav luag tsis yooj yim sua, tab sis xam nws qhov hnyav yog yooj yim heev. Piv txwv li, koj tuaj yeem ntsuas qhov piv txwv ntawm cov nyiaj thiab kwv yees tias txhua 107.8677 amu ntawm nws qhov hnyav muaj 1 atom ntawm cov nyiaj.
Kauj Ruam 2. Hloov mus rau cov pos hniav
Chav atomic pawg me me heev. Yog li, cov kws tshuaj feem ntau ntsuas cov qauv hauv grams. Hmoov zoo, lub tswv yim no tau txhais los ua kom hloov pauv tau yooj yim dua. Cias muab qhov nruab nrab atomic loj los ntawm 1 g/mol (molar mass constant) kom tau txais cov lus teb hauv g/mol. Piv txwv li, 107.8677 grams nyiaj muaj qhov nruab nrab ntawm 1 mole ntawm cov nyiaj atoms.
Kauj Ruam 3. Nrhiav qhov nruab nrab molecular loj
Txij li cov molecule yog sau los ntawm atoms, koj tuaj yeem ntxiv cov pawg ntawm cov atoms los laij cov lej molecular. Yog tias koj siv qhov nruab nrab atomic loj (tsis yog qhov hnyav ntawm qhov tshwj xeeb isotope), qhov tshwm sim yog qhov nruab nrab qhov nruab nrab ntawm cov molecules pom ib txwm muaj hauv cov qauv. Piv txwv:
- Cov dej dej muaj cov tshuaj lom neeg H2O. Yog li, nws muaj 2 hydrogen atoms (H) thiab 1 oxygen atom (O).
- Hydrogen muaj qhov nruab nrab atomic loj ntawm 1.00794 amu. Lub caij no, cov pa oxygen muaj qhov nruab nrab qhov nruab nrab ntawm 15,9994 amu.
- Molecular pawg H2Qhov nruab nrab O yog sib npaug rau (1.00794) (2) + 15.9994 = 18.01528 amu, sib npaug rau 18.01528 g/mol.
Lub tswv yim
- Lub sij hawm txheeb ze atomic mass qee zaum siv los ua cov lus sib piv rau nruab nrab atomic loj. Txawm li cas los xij, muaj qhov sib txawv me ntsis ntawm ob qhov vim tias qhov sib piv atomic loj tsis muaj chav nyob, tab sis sawv cev hnyav txheeb ze rau C-12 carbon atom. Muab koj siv cov pawg atomic loj hauv koj qhov kev suav nruab nrab, ob qhov txiaj ntsig no zoo ib yam.
- Nrog rau qee qhov tshwj xeeb tshwj xeeb, cov ntsiab lus rau sab xis ntawm lub rooj sijhawm muaj qhov nruab nrab ntau dua li cov ntsiab lus mus rau sab laug. Qhov no tuaj yeem yog txoj hauv kev yooj yim los tshuaj xyuas yog tias koj cov lus teb muaj txiaj ntsig.
- 1 atomic mass unit tau txhais tias yog 1/12 qhov hnyav ntawm ib qho C-12 carbon atom.
- Kev nplua nuj ntawm isotopes yog xam raws cov qauv uas tshwm sim ib txwm muaj nyob hauv Ntiaj Teb. Cov khoom sib txawv xws li meteorites lossis cov qauv kuaj tuaj yeem muaj qhov sib txawv ntawm isotope, thiab vim li ntawd, qhov nruab nrab nruab nrab atomic sib txawv.
- Tus lej hauv kab ntawv tom qab cov atomic loj sawv cev rau qhov tsis paub tseeb ntawm tus lej kawg. Piv txwv, qhov hnyav ntawm 1.0173 (4) txhais tau tias cov piv txwv dav dav ntawm atoms muaj qhov hnyav nyob hauv thaj tsam 1.0173 ± 0.0004. Koj tsis tas yuav siv tus lej no tshwj tsis yog nug txog qhov teeb meem.
- Siv qhov nruab nrab atomic loj thaum xam cov pawg uas cuam tshuam nrog cov ntsiab lus thiab cov sib txuas.
