Go'aamiyaa valence ee xubno ka kiimikada

Aqoonta qaabka atamka iyo taagoo qarnigii XIX ma sharixi kartaa sababta oo tiro cayiman oo atamka iskaashadaan qayb kale. Laakiin fikradaha ah aqoonyahaniinta ka hor waqtigooda, iyo valence ee weli la bartay sida mid ka mid ah mabaadiida aasaasiga ah ee kiimikada.

Laga soo bilaabo taariikhda fikirka ah "valence oo ka mid ah xubno ka kiimikada"

qarnigii XIX Heer farmashiyaha British Edvard Franklend asal ahan "isgaarsiinta" Ereyga ee isticmaalka cilmiga ah si ay u sharxaan dhexgalka ee atamka ka leh kasta oo kale. Sayniska ogaaday in qaar ka mid ah xubno ka kiimikada foomka xeryahooda la isla xaddi atamka kale. Tusaale ahaan, nitrogen qabsadey saddex atamka hydrogen ee Britain ah oo ammonia.

In May 1852 Frankland Yimaadeen la xiqiijiyay in ay jirto tiro gaar ah silsilado kiimikada in la eb sameysmi karaa iyadoo qayb kale oo yar oo arrinta. Frankland isticmaalaa weedha "ciidamo ku xira" in lagu qeexo waxa ka dib waxaa loogu yeedhi lahaa valence. farmashiyaha British aasaasay sida bonds kiimikada sameeyaan atamka qaybaha shaqsi yaqaan in bartamihii qarnigii XIX ah. Work Frankland jiray kaalin muhiim ah chemistry dhismaha casriga ah.

horumarinta views

farmashiyaha German FA Kekule cadeeyay in 1857 in carbon waa chetyrehosnovnym. In ay xarunta ugu fudud - methane - kac ay sabab u tahay 4 atamka hydrogen. Erayga "basicity" cilmiga loo isticmaalo si loogu magacaabo xubno guryaha xirmaan tiro go'an oo qayb kale. In Russia, xogta ku saabsan qaabka arrinta habeeyay A. M. Butlerov (1861). horumarinta dheeraad ah oo aragtida ah curaarta kiimikada helay waxbarista isbedelka wareegsan ee sifooyinka xubno. Its qoraaga - kale oo aad u fiican farmashiyaha Ruush D. I. Mendeleev. Waxay caddeeyeen in valence ee xubno ka kiimikada ee xeryahooda ah, iyo guryaha kale waxaa go'aamiya jago oo ay mashquulin nidaamka wareegsan.

matalaad garaafyada of valence iyo kiimikada lagala kulmo

Suurtagalnimada ee u taagoo Sawirashada - mid ka mid ah mudnaanta oo muuqda aragtida valence. Habka ugu horeysay u muuqday in 1860, iyo tan iyo 1864 ayaa la isticmaalayo qaaciidooyinka dhismaha oo ka dhigan in sumaddii kiimikada circumferential gudaha. Inta u dhaxaysa calaamadaha atamka dumisaan muujinaysaa bond kiimikada, iyo tirada khadadka waa loo siman yahay si valence ah. Sanadihii kuwa la mid ah, waxaa laga dhigay model ugu horeysay sharosterzhnevye (Photo bidixda arkaan.). In 1866 Kekule soo jeediyay hannaanka stereochemical of atamka carbon qaab tetrahedron ah, oo uu ka mid ahaa in uu buugga "Organic Chemistry".

Valence oo ka mid ah xubno ka kiimikada, iyo soo bixitaanka of xiriirka bartay by G. Lewis, kuwaas oo la daabacay shuqulladiisa 1923 ka dib markii laga helay of electron ah. Sidaas yeedhay xun eedeeyay qayb ka yar, kuwaas oo qayb ka mid ah qolofka qaaradda. In uu buugga, Lewis isticmaalo hal dhibic wareegsan oo afarta dhinacba of calaamad kiimikada ah ee soo bandhigay ee electrons valence ah.

Valency ah hydrogen iyo oxygen

Ka hor inta abuurka ah ee nidaamka wareegsan ee valence xubno kiimikada xeryahooda ah waxaa laga sameeyey inay is barbar dhigaan la atamka si taas waxaa loo yaqaan. Hydrogen iyo oxygen ayaa loo doortay tixraac. Cunsur kale oo kiimiko ah waxaa soo jiitay sidoo kale la bedelay, waayo tiro cayiman oo atamka H, iyo O.

In sidan, guryaha waxay doonayeen in a xeryahooda monovalent la hydrogen (valency ee element labaad waxaa loogu talagalay by nidaam nambaro ah Roman):

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

The oxides ee K ₂ O, CO, N ₂ O _3, SiO _2, SO ₃ ayaa lagu go'aamiyaa valence ee biraha iyo nonmetals oxygen, laban laabmay tirada atamka attachable O. helay ka dib markii qiimaha: K (I), C ( II), N (III) , Si (IV), S (VI).

Sidee si loo ogaado valence ee xubno ka kiimikada

Waxaa jira sharciyo of formation of bonds kiimikada la lammaanaha electron caadiga ah:

• valence hydrogen caadiga ah - I.
• valence oxygen caadiga ah - II.
• Waayo, xubno nonmetals-hoose valence la go'aamin karaa by formula 8 - № group, taas oo ay ku jiraan nidaamka wareegsan. Higher, haddii ay la go'aamin karaa by tirada kooxda.
• Waayo, xubno ka dhanka ah kooxaha valency ugu badan ee suurtogalka ah waa isku mid sida tirada kooxaha ee horyaalka wareegsan.

Determination of valence oo ka mid ah xubno ka kiimikada ee xarunta of formula waxaa lagu fuliyaa iyadoo la isticmaalayo geynta soo socda:

1. Record on top of qiimaha kiimikaad yaqaan ogeysiiyo mid ka mid ah waxyaabaha. Tusaale ahaan, in Mn ₂ O ₇ oxygen valency waa II.
2. Xisaabi wadarta qiimaha, oo waa loo laablaabi by valence ee tirada atamka ee element isla kiimikada Britain ee, 2 * 7 = 14.
3. Go'aaminta valency ee element labaad, taas oo ay tahay aan la garanayn. U qeybi helay Sec. 2 qiimaha by tirada atamka Mn ee Britain ayaa ku.
4. 14: 2 = 7. valence ee xabagta manganese in ay ugu sareeya - VII.

valency joogtada ah iyo variable

qiimaha Valence ah hydrogen iyo oxygen way kala duwan yihiin. Tusaale ahaan, baaruud ee xarunta of H ₂ S waa divalent, sida in formula SO ₃ - sun. carbon monoxide The sameynayso la oxygen, CO iyo CO ₂ dioxide. xarunta ugu horreeyey waa kan valence ee C II, iyo labaad - IV. Qiimaha isla methane CH _4.

Inta badan waxyaabaha ma muujiyaan valence joogto ah iyo variable, tus, fosfooraska, nitrogen, baaruud. search for sababaha ugu weyn ee this ifafaale keentay in aragtida ah ee lagala kulmo kiimikada, fikradaha electrons qolof valence, orbitals kelli. Jiritaanka qiimaha kala duwan ee guryaha isku helay oo sharaxaad ka mid ah qaab-dhismeedka atamka iyo taagoo booska.

fahmaan Modern ee valence

All atamka ka kooban yihiin xuduntii wanaagsan hareereysan electrons xun lagu soo eedeeyay. qolof dibadda, kaas oo ay u sameeyaan, waa diiqid. Dhismaha dhameystirtay waa goobta ugu xasilloon, waxa ku jira 8 electrons (octet). lagala kulmo Chemical la natiijooyinka lammaane electron caadi ah in atamka xaalad energetically wanaagsan.

Rule qaab xeryahooda waa dhamaystirka of qolof ah ama by helaya electrons recoil unpaired - ku xiran tahay in geeddi-socodka waa inuu si sahal ah. Haddii la eb siinayaa formation of bond kiimikada ah qayb ka xun isagoo labada nin ma, silsiladihiina u yeela inta ay electrons unpaired. Sida ay fikradaha casriga ah, valence ee atamka ee xubno ka kiimikada - waa awooda in ay soo saaraan dhowr ah oo qaar ka mid ah bonds covalent. Tusaale ahaan, in Britain ee, H ₂ S baaruud, tayadda hydrogen keensataa valence II (-), maxaa yeelay, eb kasta ka qayb formation of laba electron. Calaamadda "-" waxay muujinaysaa jiidashada of labada ciyaaryahan electron si element ka badan electronegative. Ugu yaraan electronegative in qiimaha valence appends "+".

Marka hab deeq-aqbalana ay lug ku leeyihiin geeddi-socodka lammaane electron mid element iyo orbitals kale valence free.

tiirsanaanta ee valence ee qaab-dhismeedka la eb ee

Ka fiirso tusaale ahaan carbon iyo oxygen, sida ay ku xiran tahay qaabka walxaha valence xubno kiimikada. Shaxda wakhtiyeysan dulmar guud ku sameynaya astaamaha aasaasiga ah ee la eb carbon ah:

• Astaanta kiimikada - C,
• Tirada shay - 6;
• lacag nuclear - 6;
• protons in xuduntii - 6;
• electron - 6, oo ay ku jiraan 4 dibadda, 2 ka mid ah oo ay u sameeyaan labo ka mid ah, 2 - unpaired.

Haddii la eb carbon foomamka laba bonds ee CO monoookside, ka dibna ay la isticmaalo waxaa loo bixiyey oo keliya 6 qayb ka xun. Si ay u bartaan octets loo baahan yahay si xubnuhu 4 sameeyay qayb ka xun dibadda. Carbon ayaa valence ah IV (+) ee dioxide iyo IV (-) ee methane.

tirada horsanaanta of oxygen - 8, qolof valence ka kooban yahay lix electrons, laba ka mid ah ay u sameeyaan labo ka mid ah oo ay ku lug leeyihiin bonds kiimikada iyo in la dhexgalo atamka kale. valence oxygen caadiga ah - II (-).

valency iyo qayilo Dawladdu waxay

Marar badan waxay u badan habboon in la isticmaalo erayga "degree of qayilo" ah. Sidaas yeedhay eb lacag taas oo ay u bartaan lahaa haddii dhan electrons ay u guureen element ku qabanaya, taas oo uu leeyahay a elektroootritsatelnosti qiimaha sare (EO). Tirada qayilo oo ah walaxda fudud waa eber. By qayilo ka badan EO daray element "-" calaamad, ka yar electronegative - "+". Tusaale ahaan, ee biraha kooxda ugu weyn ee lagu qayilo caadiga ah iyo ra'iyi eedeeyo tiro siman oo leh calaamada ah "+". Xaaladaha intooda badan gobolka valency oo lagu qayilo ee atamka ee xarunta isku mid tiro ahaan beeganto. Kaliya marka la dhexgalo atamka ka badan electronegative gobolka qayilo wanaagsan, iyadoo xubno kuwaas oo hoos EO - xun. Fikradda ah "valence ah" badanaa waxay khusaysaa oo keliya inay maal ee qaab-dhismeedka kelli.