Lub npe "atom" yog txhais los ntawm Greek li "indivisible". Txhua yam nyob ib puag ncig peb - cov khoom khib nyiab, kua thiab cua - yog tsim los ntawm ntau lab ntawm cov khoom no.
Qhov tshwm sim ntawm cov qauv hais txog lub atom
Atoms thawj zaug paub nyob rau xyoo pua 5 BC, thaum Greek philosopher Democritus tau hais tias qhov teeb meem muaj qhov txav me me. Tab sis tom qab ntawd nws tsis tuaj yeem tshawb xyuas cov version ntawm lawv lub neej. Thiab txawm hais tias tsis muaj leej twg tuaj yeem pom cov khoom no, lub tswv yim tau tham txog, vim tias tib txoj kev uas cov kws tshawb fawb tuaj yeem piav qhia txog cov txheej txheem tshwm sim hauv ntiaj teb tiag. Yog li ntawd, lawv ntseeg tias muaj cov microparticles ntev ua ntej lawv tuaj yeem ua pov thawj qhov tseeb no.
Tsuas yog xyoo 19th. lawv tau pib soj ntsuam raws li qhov tsawg tshaj plaws ntawm cov khoom siv tshuaj, muaj cov yam ntxwv tshwj xeeb ntawm cov atoms - muaj peev xwm nkag mus rau hauv cov tebchaw nrog lwm tus hauv cov nqi nruj heev. Thaum pib ntawm lub xyoo pua 20th, nws tau ntseeg tias atoms yog qhov me me ntawm cov teeb meem, txog thaum nws tau ua pov thawj tias lawv tau ua los ntawm cov khoom me me.
Yuav ua li cas yog tshuaj lom neeg ua los ntawm?
Atom ntawm cov khoom siv tshuaj lom neeg yog lub tsev me me ntawm cov teeb meem. Qhov hnyav molecular ntawm lub atom tau dhau los ua lub ntsiab lus ntawm qhov microparticle. Tsuas yog qhov kev tshawb pom ntawm Mendeleev txoj cai lij choj ib ntus tau lees paub tias lawv hom yog ntau hom ntawm ib qho teeb meem. Lawv me me heev uas lawv tsis tuaj yeem pom siv cov tshuab microscopes, tsuas yog cov khoom siv hluav taws xob muaj zog tshaj plaws xwb. Hauv kev sib piv, cov plaub hau ntawm tib neeg txhais tes yog qhov dav dua lab npaug.
Cov qauv hluav taws xob ntawm lub atom muaj cov nucleus, suav nrog cov neutrons thiab protons, nrog rau cov hluav taws xob, uas ua rau lub kiv puag ncig ntawm qhov chaw nyob rau hauv qhov chaw tas li, zoo li cov ntiaj chaw nyob ib puag ncig lawv cov hnub qub. Tag nrho cov ntawm lawv yog tuav ua ke los ntawm electromagnetic quab yuam, yog ib tug ntawm plaub lub ntsiab zog nyob rau hauv lub ntug. Neutrons yog cov khoom uas muaj cov nqi nruab nrab, cov protons tau txais txiaj ntsig nrog cov nqi zoo, thiab cov electrons nrog qhov tsis zoo. Cov yav tas yog nyiam mus rau qhov zoo nqi protons, yog li lawv nyiam nyob rau hauv orbit.
Atom qauv
Nyob rau hauv nruab nrab ib feem muaj ib tug nucleus uas sau qhov tsawg kawg nkaus ntawm tag nrho cov atom. Tab sis kev tshawb fawb qhia tias yuav luag tag nrho cov huab hwm coj (99.9%) nyob hauv nws. Txhua lub atom muaj protons, neutrons, electrons. Tus naj npawb ntawm rotating electrons nyob rau hauv nws yog sib npaug rau qhov zoo central nqi. Cov khoom uas muaj tib lub nqi hluav taws xob Z, tab sis sib txawv atomic mass A thiab tus naj npawb ntawm neutrons hauv nucleus N yog hu ua isotopes, thiab nrog tib A thiab sib txawv Z thiab N yog hu ua isobars. Electron yog qhov me me ntawm cov teeb meem nrog qhov tsis zoohluav taws xob e=1.6 10-19 coulomb. Tus nqi ntawm ib qho ion txiav txim seb cov electrons poob los yog tau txais. Tus txheej txheem ntawm metamorphosis ntawm ib tug nruab nrab atom rau hauv ib tug them ion yog hu ua ionization.
New version of the atom model
Physicists tau tshawb pom ntau lwm cov ntsiab lus rau hnub tim. Cov qauv hluav taws xob ntawm lub atom muaj qhov tshiab.
Nws ntseeg tau tias cov protons thiab neutrons, txawm tias lawv me npaum li cas, muaj cov khoom me me hu ua quarks. Lawv tsim cov qauv tshiab rau kev tsim kho ntawm lub atom. Raws li cov kws tshawb fawb tau siv los sau cov pov thawj rau qhov muaj nyob ntawm tus qauv yav dhau los, niaj hnub no lawv sim ua pov thawj qhov muaj nyob ntawm quarks.
RTM yog lub cuab yeej ntawm lub neej yav tom ntej
Cov kws tshawb fawb niaj hnub tuaj yeem pom cov atomic particles ntawm cov khoom siv ntawm lub khoos phis tawj saib, nrog rau txav mus rau saum npoo siv lub cuab yeej tshwj xeeb hu ua scanning tunneling microscope (RTM).
Qhov no yog lub cuab yeej siv computer nrog lub hau uas txav mus ze ze ntawm cov khoom. Raws li lub ntsis txav, electrons txav los ntawm qhov sib txawv ntawm lub taub thiab saum npoo. Txawm hais tias cov khoom zoo nkaus li du, nws yog qhov tsis sib xws ntawm qib atomic. Lub khoos phis tawj ua ib daim ntawv qhia ntawm qhov chaw ntawm qhov teeb meem, tsim cov duab ntawm nws cov khoom, thiab yog li cov kws tshawb fawb tuaj yeem pom cov khoom ntawm lub atom.
Radioactive particles
Tsis zoo them ions ncig ncig lub nucleus ntawm qhov deb txaus. Tus qauv ntawm lub atom yog xws li tias nws yog tag nrhoyog qhov nruab nrab tiag tiag thiab tsis muaj hluav taws xob vim tias tag nrho nws cov khoom (protons, neutrons, electrons) nyob hauv qhov sib npaug.
Ib lub atom radioactive yog ib lub caij uas tuaj yeem faib tau yooj yim. Nws qhov chaw nruab nrab muaj ntau cov protons thiab neutrons. Ib qho tshwj xeeb yog daim duab ntawm hydrogen atom, uas muaj ib qho proton. Lub nucleus yog surrounded los ntawm ib tug huab ntawm electrons, nws yog lawv attraction uas ua rau lawv tig ib ncig ntawm qhov chaw. Protons nrog tib tus nqi sib tw.
Qhov no tsis yog teeb meem rau feem ntau cov khoom me me uas muaj ob peb ntawm lawv. Tab sis qee qhov ntawm lawv tsis ruaj khov, tshwj xeeb tshaj yog cov loj xws li uranium, uas muaj 92 protons. Qee lub sij hawm nws qhov chaw tsis tuaj yeem tiv taus xws li kev thauj khoom. Lawv hu ua radioactive vim lawv emit ob peb particles ntawm lawv core. Tom qab cov nucleus tsis ruaj khov tau tshem tawm ntawm cov protons, cov protons tseem tshuav tsim ib tug ntxhais tshiab. Nws tuaj yeem ruaj khov nyob ntawm seb muaj pes tsawg tus protons hauv cov nucleus tshiab, lossis nws tuaj yeem faib ntxiv. Cov txheej txheem no txuas ntxiv mus txog thaum cov tub ntxhais kawm ruaj khov tseem nyob.
Properties of atoms
Lub cev thiab tshuaj lom neeg ntawm lub atom hloov pauv ntawm ib lub caij mus rau lwm qhov. Lawv raug txhais los ntawm cov ntsiab lus hauv qab no.
Atomic mass. Txij li qhov chaw tseem ceeb ntawm cov microparticles yog nyob ntawm protons thiab neutrons, lawv cov lej txiav txim siab tus lej, uas tau qhia hauv atomic mass units (amu) Formula: A=Z + N.
Atomic radius. Lub vojvoog nyob ntawm qhov chaw ntawm lub caij hauv Mendeleev system, tshuajbonds, tus naj npawb ntawm cov atom nyob sib ze thiab quantum mechanical action. Lub vojvoog ntawm cov tub ntxhais yog ib puas txhiab zaus me dua lub vojvoog ntawm lub caij nws tus kheej. Cov qauv ntawm lub atom tuaj yeem plam electrons thiab dhau los ua ib qho zoo ion, lossis ntxiv electrons thiab dhau los ua qhov tsis zoo ion.
Nyob rau hauv lub caij nyoog ntawm Mendeleev, txhua yam tshuaj siv nws qhov chaw. Hauv lub rooj, qhov loj ntawm lub atom nce thaum koj txav los ntawm sab saum toj mus rau hauv qab thiab txo qis thaum koj txav ntawm sab laug mus rau sab xis. Los ntawm qhov no, cov khoom me tshaj plaws yog helium thiab qhov loj tshaj plaws yog cesium.
Nyob zoo. Lub plhaub sab nraud ntawm lub atom hu ua valence plhaub, thiab cov electrons hauv nws tau txais lub npe sib xws - valence electrons. Lawv tus lej txiav txim siab seb lub atom txuas nrog rau lwm tus li cas los ntawm kev sib cog lus tshuaj. Los ntawm txoj kev tsim cov microparticle kawg, lawv sim sau lawv cov valence shells.
Kev nqus, kev nyiam yog lub zog uas ua kom lub ntiaj teb nyob hauv lub voj voog, vim tias nws cov khoom tso tawm ntawm tes poob rau hauv av. Ib tug neeg pom lub ntiajteb txawj nqus ntau dua, tab sis qhov kev ua electromagnetic muaj zog ntau zaus. Lub zog uas attracts (los yog repels) nqi hais nyob rau hauv ib tug atom yog 1,000,000,000,000,000,000,000,000,000,000,000 lub sij hawm muaj zog tshaj lub ntiajteb txawj nqus nyob rau hauv nws. Tab sis muaj ib qho tseem ceeb zog nyob rau hauv nruab nrab ntawm lub nucleus uas muaj peev xwm tuav protons thiab neutrons ua ke.
Cov tshuaj tiv thaiv hauv nuclei tsim lub zog zoo li hauv cov reactors nuclear qhov twg atoms sib cais. Qhov hnyav dua lub caij, qhov ntau qhov nws cov atoms yog tsim los ntawm. Yog tias peb ntxiv tag nrho cov protons thiab neutrons hauv ib lub caij, peb pom nwspawg. Piv txwv li, Uranium, qhov hnyav tshaj plaws nyob rau hauv cov xwm, muaj atomic loj ntawm 235 los yog 238.
Kev faib cov atom rau hauv qib
Lub zog ntawm ib lub atom yog qhov loj ntawm qhov chaw nyob ib ncig ntawm lub nucleus, qhov twg cov hluav taws xob nyob hauv kev txav. Muaj 7 orbitals nyob rau hauv tag nrho, sib raug rau cov naj npawb ntawm lub sij hawm nyob rau hauv lub periodic table. Qhov deb dua qhov chaw ntawm electron los ntawm lub nucleus, qhov tseem ceeb ntawm lub zog nws muaj. Lub sij hawm tus lej qhia tus naj npawb ntawm atomic orbitals nyob ib ncig ntawm nws cov nucleus. Piv txwv li, Potassium yog ib lub caij ntawm lub sij hawm thib 4, uas txhais tau hais tias nws muaj 4 lub zog ntawm lub atom. Tus naj npawb ntawm cov khoom siv tshuaj sib raug rau nws cov nqi thiab tus naj npawb ntawm cov electrons nyob ib ncig ntawm lub nucleus.
Atom yog lub zog
Tej zaum cov qauv kev tshawb fawb nto moo tshaj plaws tau tshawb pom los ntawm German tus kws kho mob Einstein. Nws hais tias huab hwm coj tsis muaj dab tsi tab sis ib hom ntawm lub zog. Raws li qhov kev xav no, nws muaj peev xwm tig qhov teeb meem mus rau hauv lub zog thiab xam los ntawm cov mis ntau npaum li cas ntawm nws tuaj yeem tau txais. Thawj qhov ua tau zoo ntawm qhov kev hloov pauv no yog lub foob pob atomic, uas tau sim thawj zaug hauv Los Alamos suab puam (Tebchaws Asmeskas), thiab tom qab ntawd tawg hla lub nroog Nyij Pooj. Thiab txawm hais tias tsuas yog ib feem xya ntawm qhov tawg tau hloov mus rau hauv lub zog, lub zog puas tsuaj ntawm lub foob pob atomic tau txaus ntshai.
Yuav kom cov tub ntxhais tso tawm nws lub zog, nws yuav tsum tawg. Txhawm rau faib nws, nws yog ib qho tsim nyog yuav tsum tau ua nrog lub neutron los ntawm sab nraud. Tom qab ntawd lub nucleus tawg mus rau hauv ob qho tib si, sib dua, thaum muab lub zog tso tawm loj. Kev lwj ua rau kev tso tawm ntawm lwm cov neutrons,thiab lawv tseem faib lwm cov nuclei. Cov txheej txheem hloov mus ua cov tshuaj tiv thaiv kab mob, ua rau muaj zog ntau.
Qhov zoo thiab qhov tsis zoo ntawm kev siv cov tshuaj tiv thaiv nuclear hauv peb lub sijhawm
Kev puas tsuaj quab yuam, uas tau tso tawm thaum lub sijhawm hloov pauv ntawm cov teeb meem, tib neeg tab tom sim tswj hwm ntawm nuclear fais fab nroj tsuag. Ntawm no, cov tshuaj tiv thaiv nuclear tsis tshwm sim nyob rau hauv daim ntawv ntawm kev tawg, tab sis raws li maj mam tso tawm ntawm tshav kub.
Kev tsim hluav taws xob atomic muaj nws qhov zoo thiab qhov tsis zoo. Raws li cov kws tshawb fawb, txhawm rau tswj hwm peb txoj kev vam meej nyob rau theem siab, nws yog qhov yuav tsum tau siv lub zog loj no. Tab sis nws tseem yuav tsum tau coj mus rau hauv tus account tias txawm tias kev txhim kho niaj hnub no tsis tuaj yeem lav qhov kev nyab xeeb tag nrho ntawm nuclear fais fab nroj tsuag. Tsis tas li ntawd, cov khoom siv hluav taws xob hluav taws xob tsim tawm thaum lub zog tsim hluav taws xob, yog tias khaws cia tsis raug, tuaj yeem cuam tshuam rau peb cov xeeb ntxwv rau ntau txhiab xyoo.
Tom qab muaj xwm txheej ntawm Chernobyl nuclear fais fab nroj tsuag, ntau thiab ntau tus neeg xav txog kev tsim hluav taws xob nuclear ua rau tib neeg txaus ntshai heev. Lub tsuas muaj kev nyab xeeb fais fab nroj tsuag ntawm hom no yog lub hnub nrog nws loj nuclear zog. Cov kws tshawb fawb tab tom tsim txhua yam qauv ntawm lub hnub ci hlwb, thiab tej zaum nyob rau yav tom ntej, tib neeg yuav muaj peev xwm muab nws tus kheej nrog kev nyab xeeb atomic zog.
