Itheyibhile yeperiodic sisixhobo esisisiseko kwisayensi yekhemistri. Lungiselela zonke iikhemikhali ezaziwa ngumntu ngokwenani leathom yazo kunye nezinye iimpawu zekhemikhali ezisisiseko. Nangona kunjalo, bambalwa abazaziyo iinkcukacha zemvelaphi yetheyibhile yeperiodic kunye nendlela eye yavela ngayo ekuhambeni kwexesha. Kweli nqaku, siza kuphonononga uhambo olunomdla lokudalwa kwayo kunye negalelo elibalulekileyo elenzileyo kwikhemistri yanamhlanje.
Imvelaphi yetheyibhile yeperiodic
Inguqulelo yokuqala yetafile periodic yapapashwa eJamani ngo-1869 ngusokhemisti Russian Dmitri Mendeleev. Uguqulelo lwayo lokuqala luququzelele izinto ezaziwa ngelo xesha ngokusekelwe kubunzima beathomu kunye neempawu zekhemikhali. Waseka periodicity eyenza kube nokwenzeka ukuxela kwangaphambili ubukho kunye neempawu zezakhi ezingekafunyanwa, ezifana negallium (Ga) kunye negermanium (Ge), ezafunyanwa kamva zaza zahlengahlengiswa kuqikelelo lukaMendeleev.
Izazinzulu zeli xesha sele zizame ukuhlela izinto, kodwa iziphakamiso zikaMendeleev zabangela isiseko esiluqilima. Izikhewu azishiyile etafileni yakhe azizange zibonise nje ukubakho kwezinto ezintsha, kodwa ziphinde zicebise iimpawu zabo zeekhemikhali ezisekelwe ekuqwalaselweni kweepateni kwiintsapho zezinto ezinxulumene nazo.
Imbali yetheyibhile ye periodic
Uhambo olusingise ekudalweni kwetheyibhile yeperiodic yala maxesha lwaluzele ziziganeko ezibalulekileyo. Oyena vulindlela uphambili yayingusokhemisti waseJamani uJohann Wolfgang Döbereiner, owathi ngo-1817 wahlanganisa ezinye iielementi zaba ngamathathu ngokusekwe kwiimpawu zazo ezifanayo. Oku kwaphawula enye yeenzame zokuqala zokuhlela izinto ngendlela ecwangcisiweyo, nangona isindululo sakhe sasingabanzi okanye sibandakanya zonke iinkalo.
Malunga nowe-1863, usokhemisti waseBritani uJohn Newlands wenze isindululo somthetho we-octaves, owacebisa ukuba iipropathi zeelementi ziphinda-phinda rhoqo ezisibhozo xa zicwangciswe ngokobunzima bazo beathom. Nangona umthetho wawuphumelela kwezinye iinkalo, wawusilela kwizinto ezinzima waza wagatywa ngelo xesha.
Omnye usokhemisti owayephila ngexesha likaMendeleev, uLothar Meyer, wavelisa itafile efanayo, esekelwe kumthamo weathom. Nangona uMeyer wenza igalelo elibalulekileyo, yaba nguMendeleev oye wamkelwa kakhulu ngokwembali ngenxa yokuchaneka koqikelelo lwakhe.
Impumelelo eqinisekileyo yetheyibhile yeperiodic yeza ngo-1913 kunye nosokhemisti waseBritane uHenry Moseley, owagqiba ukuba inani leathomu, hayi ubunzima beathom, yayiyeyona nto imisela iipropathi zezinto. Moseley wenza oku kufunyaniswe usebenzisa izifundo X-reyi, nto leyo eyenza kube nokwenzeka ukulungisa ezinye ukungangqinelani ezazikho kwitafile Mendeleev kaThixo.
Amaqela etafile ye periodic
Iziqalelo zetheyibhile yeperiodic zihlelwe ngokweentsika ezili-18 ezithe nkqo, ezaziwa njengamaqela okanye iintsapho. Ezi zinto zeqela ezinolungelelwaniso lwe-elektroniki olufana kakhulu kunye neempawu zekhemikhali. Eminye imizekelo ephawulekayo yile:
- Iqela 1: Iintsimbi zealkali, ezifana ne-lithium (Li), i-sodium (Na) kunye ne-potassium (K). Zizinto ezisebenzayo ngokumangalisayo, ngakumbi ngamanzi, kwaye zenze iikhompawundi ezine-halogens, umzekelo, iityuwa eziqhelekileyo ezifana ne-sodium chloride.
- Iqela 17: I-halogens, njenge-fluorine (F), i-chlorine (Cl) kunye ne-bromine (Br). Ezi zinto ziyasebenza kwaye zenza iikhompawundi ezifana neeasidi kunye neetyuwa zentsimbi ngokulula.
- Iqela 18: Iigesi ezibalaseleyo, ezibandakanya i-helium (He), neon (Ne), kunye ne-argon (Ar). Ziyi-inert yekhemikhali ngenxa yokucwangciswa kwazo okupheleleyo kwe-elektroniki, okubanika uzinzo kwaye kubathintele ekubeni benze iikhompawundi ngokulula.
Ngalinye lala maqela limele iimpawu ezikwabelwana ngazo ngezinto eziziquletheyo, eziye zavumela izazinzulu ukuba ziqikelele ngokuchanekileyo ukuziphatha kweekhemikhali kunye neempendulo ngokuhamba kwexesha.
Okwangoku, itheyibhile yeperiodic iqulethe izinto ezili-118, apho ezingama-94 zifumaneka kwindalo, ngelixa ezinye zenziwe ngokuzenzekelayo kwiilabhoratri. Uphando luyaqhubeka nokudibanisa izinto ezintsha, kunye neelebhu zaseJapan, eRussia, eUnited States naseJamani zikhuphisana ekufumaneni izinto ezinamanani eathom angaphezu kwe-118.
Inguqulelo yanamhlanje yetheyibhile yeperiodic sisiphumo sendaleko eye yenzeka ngaphezu kwenkulungwane, egqibelele ngenkqubela yenzululwazi. Ngenkulungwane ye-20 kunye ne-21, izinto ezifana ne-oganeson (Og), i-moscovium (Mc) kunye ne-nihonium (Nh) yongezwa ngenxa yemigudu ekudaleni izinto zokwenziwa.
Itheyibhile yeperiodic iyaqhubeka nokuba sesinye sezona zixhobo zibaluleke kakhulu kwisayensi yemichiza, kuba ayicaluli nje kuphela izinto, kodwa ikwasivumela ukuba siqikelele iipropati zabo kunye neekhemikhali. Ukucwangciswa kwezinto ngokobume be-elektroniki kukwavule imilinganiselo emitsha kwifiziksi kunye nezinye isayensi yendalo.
Esi sixhobo, esaqala ngokuqatshelwa kwesazinzulu esinye, siye sakhula saba yimephu yeebhloko ezisisiseko zezinto. Ukuziphendukela kwemvelo kwayo kuya kuqhubeka, kodwa ihlala isisiseko sokuqonda isayensi yendalo yonke kunye nokusebenzisana okuntsonkothileyo kwezinto eziyibumbayo.