Ƙaddara da valence da sinadaran abubuwa

Ilimi na tsarin kwayoyin zarra da kwayoyin a cikin XIX karni ba zai iya bayyana dalilin da wani yawan sunadaran samar da shaidu da sauran barbashi. Amma ra'ayoyin masana kimiyya gaba na lokaci, da kuma valence na har yanzu ana yi karatu a matsayin daya daga cikin ka'idojin da sunadarai.

Daga cikin tarihi na manufar "valence da sinadaran abubuwa"

Fice Birtaniya sunadarai XIX karni Edvard Franklend buga da Kalmar "sadarwa" a cikin kimiyya amfani da su bayyana hulda da sunadaran da juna. Kimiyya lura cewa, wasu sinadaran abubuwa samar mahadi da wannan adadin wasu kwayoyin halitta. Alal misali, nitrogen dora uku hydrogen atoms a wani kwayoyin na ammonia.

A May 1852 Frankland sa a gaba da suke cewa akwai wani takamaiman adadin sinadaran shaidu cewa zarra na iya samar da wasu kankanin barbashi al'amarin. Frankland amfani da furcin nan "a haɗa karfi", don bayyana abin da zai daga baya za a kira valence. Birtaniya sunadarai kafa a matsayin sinadaran shaidu samar da sunadaran mutum abubuwa da aka sani a tsakiyar XIX karni. Aiki Frankland ya na da muhimmanci taimako ga zamani tsarin sunadarai.

ci gaban da ra'ayoyi

Jamus sunadarai FA Kekule tabbatar a 1857 cewa carbon ne chetyrehosnovnym. A ta sauki fili - methane - bayyana saboda 4 hydrogen atoms. Kalmar "basicity" masanin kimiyyar amfani designate abubuwa Properties connect wani tsayayyen yawan sauran barbashi. A Rasha, da bayanai a kan tsarin da al'amari systematized A. M. Butlerov (1861). Kara ci gaba da ka'idar sinadaran bond samu ta hanyar koyarwar lokaci-lokaci canji a cikin kaddarorin da abubuwa. Its marubucin - wani fice Rasha sunadarai D. I. Mendeleev. Yana tabbatar da cewa valence da sinadaran abubuwa a cikin mahadi, da sauran kaddarorin aka ƙaddara da matsayi wanda suka zauna a cikin lokaci-lokaci tsarin.

Zana wakilci na valence da kuma sinadaran bonding

The yiwuwar visualizing kwayoyin - daya daga cikin undoubted isa yabo na valence ka'idar. A farko model bayyana a 1860, kuma tun 1864 da aka yin amfani da tsarin dabarbari wakiltar sinadaran circumferential alamar ciki. Tsakanin alamomin dash atoms denoted sinadaran bond, da kuma yawan Lines ne daidaita da valence. A waɗannan shekaru iri guda, da aka yi da farko sharosterzhnevye model (ga. Photo a kan hagu). A 1866 Kekule samarwa stereochemical juna na carbon atoms a cikin wani nau'i na tetrahedron, wanda ya hada da a cikin littafi "Organic Chemistry".

Valence da sinadaran abubuwa, da kuma fitowan da dangantaka karatu da G. Lewis, wanda aka buga ayyukansa a shekarar 1923 bayan da samu na electron. Don haka ya kira barnatar da cajin kankanin gaɓũɓuwa, wanda wani bangare ne na atomic bawo. A cikin littafinsa, Lewis amfani da wani batu a kusurwoyi huɗu na da sinadaran alama ce ga nuni da valence electrons.

Valency na hydrogen da oxygen

Kafin halittar da lokaci-lokaci tsarin na valence da sinadaran abubuwa a cikin mahadi da aka sanya don kwatantawa tare da sunadaran don wanda shi aka sani. Hydrogen da oxygen da aka zaba a matsayin tunani. Wani sinadari ne janyo hankalin ko dai sauya ga wani yawan H kwayoyin halitta, kuma O.

A cikin wannan hanya, da kaddarorin da aka ƙayyade cikin wani monovalent mahadi da hydrogen (da valency na biyu kashi ne kaddamarda da Roman adadi):

• HCI - chloro (I):
• H ₂ O - oxygen (II);
• NH ₃ - nitrogen (III).
• CH ₄ - carbon (IV).

A oxides na K ₂ Ya, CO, N ₂ Ya _3, Sio _2, SO ₃ da aka ƙaddara da valence da karafa da kuma nonmetals oxygen, anya yawan sunadaran attachable O. Samu wadannan dabi'u: K (I), C ( II), N (III) , Si (IV), S (VI).

Ta yaya domin sanin valence da sinadaran abubuwa

Akwai dokoki na samuwar sinadaran shaidu da kowa electron nau'i-nau'i:

• Hankula hydrogen valence - I.
• Al'ada oxygen valence na - II.
• Domin abubuwa nonmetals-ƙananan valence za a iya ƙaddara da dabara 8 - № kungiyar a cikin abin da suka kasance a cikin lokaci-lokaci tsarin. Higher, idan shi za a iya ƙaddara da kungiyar lambar.
• Domin gefen abubuwa na subgroups iyakar yiwu valency ne guda a matsayin yawan kungiyoyin a cikin lokaci-lokaci tebur.

Tabbatar da dalilin da valence da sinadaran abubuwa na fili da dabara ne da za'ayi amfani da wadannan algorithm:

1. Record a saman chemically saba a san da darajar for daya daga cikin abubuwa. Alal misali, a mn ₂ Ya ₇ oxygen valency ne II.
2. Lissafi da duka darajar, wanda dole ne su yawaita da valence na yawan kwayoyin zarra daga cikin wannan sinadari a cikin DNA, 2 * 7 = 14.
3. Ƙayyade da valency na biyu da rabi, wanda shi ne ba a sani ba. Raba samu a Sec. 2 darajar da yawan mn kwayoyin halitta a cikin kwayoyin.
4. 14: 2 = 7. The valence na manganese oxide a qarshe - VII.

Dindindin kuma m valency

Valence dabi'u na hydrogen da oxygen ne daban-daban. Alal misali, sulfur a fili na H ₂ S ne divalent, kamar yadda a cikin dabara SO ₃ - hexavalent. A carbon monoxide reacts tare da oxygen, CO da CO ₂ dioxide. A farko fili ne valence na C II, da kuma a karo na biyu - IV. A wannan darajar a methane CH _4.

Mafi yawa daga cikin abubuwa ba ya nuna m, kuma m valence, msl, phosphorus, nitrogen, sulfur. The search for babban Sanadin wannan sabon abu ya jagoranci wani ka'idar sinadaran bonding, Concepts valence harsashi electrons, kwayoyin orbitals. A zama na daban-daban dabi'u na wannan Properties samu tare da bayani na tsarin kwayoyin zarra da kwayoyin matsayi.

Modern tunanin na valence

All atoms an hada da m tsakiya kewaye da barnatar da cajin electrons. A matsanancin harsashi, wanda suka samar, shi ne wanda ba a kare. A kammala tsari ne mafi barga, shi ya ƙunshi 8 electrons (bane). Chemical bonding tare da kowa electron nau'i-nau'i sakamakon a energetically m yanayin kwayoyin halitta.

Rule da samuwar mahadi ne kammala wani harsashi ko ta hanyar karbar electrons recoil unpaired - dangane da ko aiwatar da sauki ga wuce. Idan zarra na samar da samuwar wani sinadaran bond korau barbashi da ciwon wani biyu, da shaidu shi Forms muddin dai unpaired electrons. Kamar yadda zamani Concepts, da valence na sunadaran sinadaran abubuwa - ne da ikon samar da wani yawan covalent shaidu. Alal misali, a cikin DNA, H ₂ S sulfur, hydrogen sulfide yakan mallaki valence II (-), domin kowane zarra taka rawa a cikin samuwar biyu electron nau'i-nau'i. The alamar "-" na nuna janye daga electron biyu da mafi electronegative kashi. A kalla electronegative ga darajar valence appends "+".

Lokacin da mai bayarwa-Mai karɓar inji suna da hannu a aiwatar da electron nau'i-nau'i daga daya kashi da kuma sauran free valence orbitals.

A dogara da valence na tsarin da zarra

La'akari da misali carbon da oxygen, kamar yadda shi ya dogara da tsarin da abubuwa valence da sinadaran abubuwa. Lokaci-lokaci Table ba wani bayyani na asali halaye na carbon zarra:

• sinadaran da alama - C;
• abu lambar - 6;
• nukiliya cajin - 6;
• protons a tsakiya - 6;
• electron - 6, ciki har da 4 waje, 2 daga wanda ya samar da wani biyu, 2 - unpaired.

Idan carbon zarra suranta biyu shaidu a monoookside CO, sa'an nan ta yi amfani da ake kawota kawai 6 korau barbashi. Don saya octets bukatar ware 4 kafa waje korau barbashi. Carbon yana da wani valence na IV (+) a dioxide da kuma IV (-) a methane.

Ordinal yawan oxygen - 8, da valence harsashi kunshi shida electrons, biyu daga cikinsu ya samar da wata biyu, kuma suna da hannu a cikin sinadaran shaidu da kuma hulda da sauran kwayoyin halitta. Hankula oxygen valence - II (-).

A valency da hadawan abu da iskar shaka jihar

A lokuta da dama, shi ne mafi dace don amfani da Kalmar "mataki na hadawan abu da iskar shaka". Don haka ya kira cajin zarra wanda zai saya idan duk electrons sun mayar da su cikin dauri kashi, wanda yana da mafi girma darajar elektroootritsatelnosti (eo). A hadawan abu da iskar shaka da dama daga cikin sauki abu ne sifili. By hadawan abu da iskar shaka mafi eo kara kashi "-" ãyã, kasa electronegative - "+". Alal misali, babban kungiyar karafa domin hankula hadawan abu da iskar shaka da kuma ion zarginta da daidai lambar da alamar "+". A mafi yawan lokuta da valency da hadawan abu da iskar shaka Jihar kwayoyin halitta a cikin wannan fili numerically daidaita. Kawai a lokacin da hulda da mafi electronegative atoms m hadawan abu da iskar shaka jihar, tare da abubuwa wanda eo kasa - korau. A ra'ayi na "valence na" sau da yawa ya shafi kawai ga abu daga cikin kwayoyin tsarin.