Halogens nyob rau hauv lub sij hawm lub sij hawm yog nyob rau sab laug ntawm noble gases. Cov tsib yam tshuaj lom uas tsis yog-hlau yog nyob rau hauv pawg 7 ntawm lub sij hawm. Cov no suav nrog fluorine, chlorine, bromine, iodine thiab astatine. Txawm hais tias astatine yog cov xov tooj cua thiab tsuas muaj cov isotopes luv luv xwb, nws coj zoo li iodine thiab feem ntau suav tias yog halogen. Txij li thaum cov ntsiab lus halogen muaj xya valence electrons, lawv tsuas xav tau ib qho hluav taws xob ntxiv los ua ib qho octet tag nrho. Cov yam ntxwv no ua rau lawv muaj kev cuam tshuam ntau dua li lwm pab pawg uas tsis yog hlau.
yam ntxwv dav dav
Halogens tsim diatomic molecules (ntawm hom X 2, qhov twg X qhia txog halogen atom) - daim ntawv ruaj khov ntawm lub neej ntawm halogens hauv daim ntawv dawb. Cov ntawv cog lus ntawm cov diatomic molecules no tsis yog-polar, covalent thiab ib leeg. Cov khoom siv tshuaj lom neeg ntawm halogens tso cai rau lawv yooj yim ua ke nrog ntau lub ntsiab lus, yog li lawv tsis tshwm sim tsis sib xws hauv qhov xwm txheej. Fluorine yog qhov nquag halogen thiab astatin tsawg tshaj plaws.
Txhua halogens tsim pab pawg kuv ntsev nrog zoo sib xwskhoom. Hauv cov tebchaw no, halogens tam sim no yog halide anions nrog tus nqi ntawm -1 (piv txwv li, Cl-, Br-). Qhov kawg -id qhia tias muaj cov halide anions; e.g. Cl- hu ua "chloride".
Ntxiv rau, cov khoom siv tshuaj lom neeg ntawm halogens tso cai rau lawv los ua cov tshuaj oxidizing - kom oxidize hlau. Feem ntau cov tshuaj tiv thaiv nrog halogens yog cov tshuaj tiv thaiv redox hauv cov kua dej. Halogens tsim ib daim ntawv cog lus nrog carbon lossis nitrogen hauv cov organic tebchaw uas lawv lub xeev oxidation (CO) yog -1. Thaum lub halogen atom hloov los ntawm covalently bonded hydrogen atom nyob rau hauv ib tug organic compound, lub prefix halo- yuav siv tau nyob rau hauv ib tug general kev txiav txim zoo, los yog lub prefixes fluoro-, chloro-, bromine-, iodine- rau tej halogens. Halogen cov ntsiab lus tuaj yeem raug sib txuas los tsim cov kab mob diatomic nrog cov polar covalent ib daim ntawv cog lus.
Chlorine (Cl2) yog thawj halogen pom nyob rau xyoo 1774, tom qab ntawd los ntawm iodine (I2), bromine (Br) 2), fluorine (F2) thiab astatine (Ntawm, nrhiav pom kawg, xyoo 1940). Lub npe "halogen" los ntawm Greek cov hauv paus hniav hal- (" ntsev") thiab -gen ("rau tsim"). Ua ke, cov lus no txhais tau tias "tsim ntsev", hais txog qhov tseeb tias halogens hnov mob nrog hlau los ua ntsev. Halite yog lub npe ntawm pob zeb ntsev, ib qho ntxhia ntuj tsim los ntawm sodium chloride (NaCl). Thiab thaum kawg, halogens tau siv nyob rau hauv lub neej txhua hnub - fluoride muaj nyob rau hauv cov tshuaj txhuam hniav, chlorine disinfects dej haus, thiab iodine txhawb kev tsim cov tshuaj hormones.cov thyroid.
tshuaj lom neeg
Fluorine yog ib yam khoom uas muaj tus lej atomic 9, txhais los ntawm lub cim F. Elemental fluorine tau pom thawj zaug hauv xyoo 1886 los ntawm kev cais tawm ntawm hydrofluoric acid. Nyob rau hauv nws lub xeev dawb, fluorine muaj nyob raws li ib tug diatomic molecule (F 2) thiab yog halogen ntau tshaj plaws nyob rau hauv lub ntiaj teb crust. fluorine yog cov khoom electronegative tshaj plaws nyob rau hauv lub sij hawm. Nyob rau hauv chav tsev kub, nws yog daj ntseg daj. Fluorine kuj muaj qhov me me atomic radius. Nws CO yog -1, tshwj tsis yog rau lub xeev diatomic elemental, uas nws lub xeev oxidation yog xoom. Fluorine yog qhov muaj zog heev thiab cuam tshuam ncaj qha nrog txhua yam tshwj tsis yog helium (He), neon (Ne), thiab argon (Ar). Hauv H2O tov, hydrofluoric acid (HF) yog cov kua qaub tsis muaj zog. Txawm hais tias fluorine muaj zog electronegative, nws cov electronegativity tsis txiav txim siab acidity; HF yog cov kua qaub tsis muaj zog vim qhov tseeb tias fluorine ion yog qhov yooj yim (pH> 7). Tsis tas li ntawd, fluorine tsim cov oxidizers muaj zog heev. Piv txwv li, fluorine tuaj yeem hnov mob nrog cov roj tsis muaj zog xenon los tsim cov tshuaj muaj zog oxidizing xenon difluoride (XeF2). Fluorine muaj ntau yam siv.
Chlorine yog ib yam khoom uas muaj atomic tooj 17 thiab cov cim tshuaj Cl. Tshawb nrhiav hauv 1774 los ntawm kev cais nws los ntawm hydrochloric acid. Nyob rau hauv nws lub xeev elemental, nws tsim ib tug diatomic molecule Cl2. Chlorine muaj ob peb COs: -1, +1, 3, 5 thiab7. Nyob rau hauv chav tsev kub, nws yog lub teeb ntsuab ntsuab. Txij li thaum daim ntawv cog lus uas tsim los ntawm ob lub chlorine atoms tsis muaj zog, Cl 2molecule muaj peev xwm nkag mus rau hauv cov tebchaw. chlorine reacts nrog hlau los tsim cov ntsev hu ua chlorides. Chlorine ions yog cov ions ntau tshaj plaws nyob rau hauv dej hiav txwv. Chlorine kuj muaj ob lub isotopes: 35 Cl thiab 37 Cl. Sodium chloride yog feem ntau ntawm tag nrho cov chlorides.
Bromine yog cov khoom siv tshuaj lom neeg nrog atomic tooj 35 thiab cim Br. Nws yog thawj zaug pom nyob rau hauv 1826. Nyob rau hauv nws cov elemental daim ntawv, bromine yog ib tug diatomic molecule Br2. Nyob rau hauv chav tsev kub, nws yog ib tug reddish-xim av kua. Nws cov CO yog -1, +1, 3, 4 thiab 5. Bromine muaj zog dua li iodine, tab sis tsawg dua chlorine. Tsis tas li ntawd, bromine muaj ob lub isotopes: 79 Br thiab 81 Br. Bromine tshwm sim li bromide ntsev yaj hauv dej hiav txwv. Nyob rau hauv xyoo tsis ntev los no, zus tau tej cov bromide nyob rau hauv lub ntiaj teb no tau nce ntau vim nws muaj thiab lub neej ntev. Zoo li lwm yam halogens, bromine yog tus neeg sawv cev oxidizing thiab muaj tshuaj lom heev.
Iodine yog ib yam tshuaj muaj atomic tooj 53 thiab cim I. Iodine muaj oxidation xeev: -1, +1, +5 thiab +7. Muaj raws li ib tug diatomic molecule, I2. Nyob rau hauv chav tsev kub nws yog xim liab. Iodine muaj ib qho isotope ruaj khov, 127 I. Thawj zaug pom nyob rau hauv 1811nrog seaweed thiab sulfuric acid. Tam sim no, iodine ions tuaj yeem cais tawm hauv dej hiav txwv. Txawm hais tias iodine tsis soluble hauv dej, nws cov solubility tuaj yeem nce ntxiv los ntawm kev siv cov iodide cais. Iodine ua lub luag haujlwm tseem ceeb hauv lub cev, koom nrog hauv kev tsim cov thyroid hormones.
Astatine yog cov khoom siv hluav taws xob muaj hluav taws xob nrog tus lej atomic 85 thiab cim At. Nws muaj peev xwm oxidation xeev yog -1, +1, 3, 5, thiab 7. Tsuas yog halogen uas tsis yog diatomic molecule. Nyob rau hauv tej yam kev mob, nws yog ib tug dub metallic khoom. Astatine yog ib yam khoom uas tsis tshua muaj, yog li me ntsis paub txog nws. Tsis tas li ntawd, astatine muaj ib nrab-lub neej luv luv, tsis ntev tshaj li ob peb teev. Tau txais nyob rau hauv 1940 raws li ib tug tshwm sim ntawm synthesis. Nws ntseeg tau tias astatine zoo ib yam li iodine. Features metallic zog.
Cov lus hauv qab no qhia cov qauv ntawm halogen atoms, cov qauv ntawm txheej txheej ntawm electrons.
| Halogen | Electron configuration |
| Fluorine | 1s22s2 2p5 |
| Chlorine | 3s23p5 |
| Bromine | 3d104s2 4p5 |
| Iodine | 4d105s25p5 |
| Astatine | 4f145d106s2 6p5 |
Cov qauv zoo sib xws ntawm txheej txheej electrons txiav txim siab tias lub cev thiab tshuaj lom neeg ntawm halogens zoo ib yam. Txawm li cas los xij, thaum sib piv cov ntsiab lus, qhov sib txawv kuj tau pom.
Lub sijhawm lub sijhawm nyob hauv pawg halogen
Lub cev lub cev ntawm cov khoom yooj yim halogens hloov nrog nce cov lej. Rau kev nkag siab zoo dua thiab pom meej dua, peb muab ntau lub rooj rau koj.
Cov ntsiab lus melting thiab boiling ntawm pab pawg nce raws li qhov loj ntawm cov molecule nce (F <Cl
Table 1. Halogens. Lub cev muaj zog: melting thiab boiling cov ntsiab lus
| Halogen | Melting T (˚C) | Boiling point (˚C) |
| Fluorine | -220 | -188 |
| Chlorine | -101 | -35 |
| Bromine | -7.2 | 58.8 |
| Iodine | 114 | 184 |
| Astatine | 302 | 337 |
Atomic radius nce
Qhov loj ntawm lub nucleus nce (F < Cl < Br < I < Ntawm), raws li tus naj npawb ntawm cov protons thiab neutrons nce. Tsis tas li ntawd, ntau thiab ntau lub zog ntxiv nrog rau txhua lub sijhawm. Qhov no ua rau lub orbital loj dua, thiab yog li ntawd qhov kev nce hauv lub vojvoog ntawm lub atom.
Table 2. Halogens. Lub cev muaj zog: atomic radii
| Halogen | Covalent radius (pm) | Ionic (X-) radius (pm) |
| Fluorine | 71 | 133 |
| Chlorine | 99 | 181 |
| Bromine | 114 | 196 |
| Iodine | 133 | 220 |
| Astatine | 150 |
Ionization zog txo
Yog tias sab nraud valence electrons tsis nyob ze ntawm lub nucleus, ces nws yuav tsis siv zog ntau los tshem tawm ntawm nws. Yog li, lub zog uas yuav tsum tau thawb cov hluav taws xob sab nraud tawm tsis yog siab nyob rau hauv qab ntawm pawg pawg, vim tias muaj ntau lub zog. Tsis tas li ntawd, lub zog ionization siab ua rau lub caij ua kom pom cov khoom tsis yog xim hlau. Iodine thiab astatine tso saib cov khoom siv hlau vim tias lub zog ionization txo qis (Ntawm < I < Br < Cl < F).
Table 3. Halogens. Lub cev muaj zog: ionization zog
| Halogen | Ionization zog (kJ/mol) |
| fluorine | 1681 |
| chlorine | 1251 |
| bromine | 1140 |
| Iodine | 1008 |
| astatin | 890 ± 40 |
Electronegativity txo qis
Tus naj npawb ntawm valence electrons hauv ib lub atom nce nrog nce zog ntawm qib qis dua. Cov electrons tau nce mus deb ntawm lub nucleus; Yog li ntawd, lub nucleus thiab electrons tsis yog ob leeg attracted rau ib leeg. Kev nce hauv kev tiv thaiv yog pom. Yog li ntawd, Electronegativity txo qis nrog lub sijhawm nce (ntawm < I < Br < Cl < F).
Table 4. Halogens. Lub cev muaj zog: electronegativity
| Halogen | Electronegativity |
| fluorine | 4.0 |
| chlorine | 3.0 |
| bromine | 2.8 |
| Iodine | 2.5 |
| astatin | 2.2 |
Electron affinity txo
Raws li qhov loj ntawm lub atom nce nrog lub sij hawm nce, electron affinity yuav txo qis (B < I < Br < F < Cl). Ib qho tshwj xeeb yog fluorine, nws qhov kev sib raug zoo tsawg dua li cov tshuaj chlorine. Qhov no tuaj yeem piav qhia los ntawm qhov me me ntawm fluorine piv rau chlorine.
Table 5. Electron affinity of halogens
| Halogen | Electron affinity (kJ/mol) |
| fluorine | -328.0 |
| chlorine | -349.0 |
| bromine | -324.6 |
| Iodine | -295.2 |
| astatin | -270.1 |
Reactivity ntawm cov ntsiab txo qis
Lub reactivity ntawm halogens txo nrog nce lub sij hawm (ntawm <I
Inorganic chemistry. Hydrogen + halogens
Ib halide yog tsim thaum lub halogen reacts nrog lwm yam, tsawg electronegative caij los tsim ib tug binary compound. Hydrogen reacts nrog halogens los ua HX halides:
- hydrogen fluoride HF;
- hydrogen chloride HCl;
- hydrogen bromide HBr;
Yhydrioodine HI.
Hydrogen halides yooj yim yaj hauv dej los ua hydrohalic (hydrofluoric, hydrochloric, hydrobromic, hydroiodic) acids. Cov khoom ntawm cov kua qaub no tau muab hauv qab no.
Acids yog tsim los ntawm cov tshuaj tiv thaiv hauv qab no: HX (aq) + H 2O (l) → Х- (aq) +H 3O+ (aq).
Tag nrho cov hydrogen halides tsim muaj zog acids tshwj tsis yog HF.
Lub acidity ntawm hydrohalic acids nce: HF <HCl <HBr <HI.
Hydrofluoric acid tuaj yeem kos iav thiab qee cov fluorides inorganic rau lub sijhawm ntev.
Nws yuav zoo li qhov tsis txaus ntseeg tias HF yog qhov tsis muaj zog tshaj plaws hydrohalic acid, vim tias fluorine muaj qhov siab tshaj plawselectronegativity. Txawm li cas los xij, H-F daim ntawv cog lus muaj zog heev, ua rau cov kua qaub tsis muaj zog heev. Ib daim ntawv cog lus muaj zog yog txiav txim siab los ntawm qhov luv luv daim ntawv cog lus thiab lub zog sib cais siab. Ntawm tag nrho cov hydrogen halides, HF muaj qhov luv tshaj daim ntawv cog lus ntev thiab lub zog loj tshaj plaws ntawm kev sib koom ua ke.
Halogen oxoacids
Halogen oxoacids yog cov kua qaub nrog hydrogen, oxygen thiab halogen atoms. Lawv acidity tuaj yeem txiav txim siab siv cov qauv ntsuas. Halogen oxoacids muaj npe hauv qab no:
- Hypochlorous acid HOCl.
- Chloric acid HClO2.
- Chloric acid HClO3.
- Perchloric acid HClO4.
- Hypochlorous acid HOBr.
- Bromomic acid HBrO3.
- Bromoic acid HBrO4.
- Iodonic acid HIO3.
- Methaiodic acid HIO4, H5IO6.
YHyiodic acid HOI.
Nyob rau hauv txhua yam ntawm cov kua qaub no, ib tug proton yog bonded rau ib tug oxygen atom, yog li muab piv proton daim ntawv cog lus ntev yog tsis muaj txiaj ntsig ntawm no. Electronegativity plays lub luag haujlwm tseem ceeb ntawm no. Kev ua kua qaub nce nrog cov pa oxygen atoms khi rau hauv nruab nrab atom.
Zoo thiab lub xeev teeb meem
Lub cev lub cev tseem ceeb ntawm halogens tuaj yeem sau tseg hauv cov lus hauv qab no.
| Lub xeev teeb meem (ntawm chav tsev kub) | Halogen | Zoo |
| nyuaj | Iodine | ntsuab |
| astatin | dub | |
| kua | bromine | red-xim av |
| fluorine | paj tan | |
| chlorine | paj ntsuab |
Zoo piav qhia
Cov xim ntawm halogens yog qhov tshwm sim ntawm kev nqus ntawm pom lub teeb los ntawm cov molecules, uas ua rau lub zog ntawm electrons. Fluorine absorbs violet lub teeb thiab yog li pom lub teeb daj. Iodine, ntawm qhov tod tes, absorbs daj lub teeb thiab tshwm liab doog (daj thiab ntshav yog cov xim sib xyaw). Cov xim ntawm halogens dhau los ua tsaus nti thaum lub sijhawm nce.
Hauv cov thawv kaw, cov kua bromine thiab cov khoom iodine nyob rau hauv qhov sib npaug nrog lawv cov vapors, uas tuaj yeem pom raws li cov roj pleev xim.
Txawm hais tias cov xim ntawm astatine tsis paub, nws tau xav tias nws yuav tsum tsaus dua li iodine (piv txwv li dub) raws li cov qauv pom.
Tam sim no, yog tias koj raug nug: "Cim lub cev lub zog ntawm halogens", koj yuav muaj qee yam hais.
Lub xeev oxidation ntawm halogens hauv cov tebchaw
Oxidation xeev feem ntau siv tsis yog "halogen valency". Raws li txoj cai, lub xeev oxidation yog -1. Tab sis yog tias halogen txuas nrog oxygen lossis lwm lub halogen, nws tuaj yeem ua rau lwm lub xeev:CO oxygen -2 muaj qhov tseem ceeb. Nyob rau hauv rooj plaub ntawm ob txawv halogen atoms sib txuas ua ke, ntau electronegative atom prevails thiab siv CO -1.
Piv txwv li, hauv iodine chloride (ICl) chlorine muaj CO -1, thiab iodine +1. Chlorine yog ntau electronegative tshaj iodine, yog li nws CO yog -1.
Hauv bromic acid (HBrO4) oxygen muaj CO -8 (-2 x 4 atoms=-8). Hydrogen muaj tag nrho oxidation xeev ntawm +1. Ntxiv cov nqi no muab CO -7. Txij li thaum kawg CO ntawm qhov sib xyaw yuav tsum yog xoom, CO ntawm bromine yog +7.
Qhov thib peb qhov kev zam rau txoj cai yog lub xeev oxidation ntawm halogen hauv daim ntawv elemental (X2), qhov twg nws CO yog xoom.
| Halogen | CO in compounds |
| fluorine | -1 |
| chlorine | -1, +1, +3, +5, +7 |
| bromine | -1, +1, +3, +4, +5 |
| Iodine | -1, +1, +5, +7 |
| astatin | -1, +1, +3, +5, +7 |
Vim li cas SD ntawm fluorine ib txwm -1?
Electronegativity nce nrog lub sijhawm. Yog li ntawd, fluorine muaj lub siab tshaj plaws electronegativity ntawm tag nrho cov ntsiab, raws li muaj pov thawj los ntawm nws txoj hauj lwm nyob rau hauv lub periodic rooj. Nws txoj kev teeb tsa hluav taws xob yog 1s2 2s2 2p5. Yog tias fluorine tau txais ib qho hluav taws xob ntxiv, qhov sab nraud p-orbitals tau puv tag nrho thiab ua kom tag nrho octet. Vim muaj fluorinesiab electronegativity, nws tuaj yeem yooj yim nqa ib qho hluav taws xob los ntawm ib qho atom nyob sib ze. Fluorine nyob rau hauv cov ntaub ntawv no yog isoelectronic rau cov inert gas (nrog yim valence electrons), tag nrho nws cov sab orbitals yog sau. Hauv lub xeev no, fluorine ruaj khov dua.
Kev tsim khoom thiab siv halogens
Nyob rau hauv xwm, halogens nyob rau hauv lub xeev ntawm anions, yog li dawb halogens tau los ntawm oxidation los ntawm electrolysis los yog siv oxidizing agents. Piv txwv li, chlorine yog tsim los ntawm hydrolysis ntawm ntsev tov. Kev siv halogens thiab lawv cov tebchaw muaj ntau yam.
- Fluorine. Txawm hais tias fluorine yog reactive heev, nws yog siv nyob rau hauv ntau daim ntawv thov kev lag luam. Piv txwv li, nws yog ib qho tseem ceeb ntawm polytetrafluoroethylene (Teflon) thiab lwm yam fluoropolymer. CFCs yog cov tshuaj organic uas yav tas los tau siv los ua cov tub yees thiab cov tshuaj tiv thaiv hauv aerosols. Lawv siv tau tso tseg vim lawv muaj feem cuam tshuam rau ib puag ncig. Lawv tau hloov los ntawm hydrochlorofluorocarbons. Fluoride ntxiv rau cov tshuaj txhuam hniav (SnF2) thiab haus dej (NaF) txhawm rau tiv thaiv cov hniav lwj. Cov halogen no muaj nyob rau hauv cov av nplaum siv los ua qee hom ceramics (LiF), siv hauv nuclear fais fab (UF 6), los tsim cov tshuaj tua kab mob fluoroquinolone, txhuas (Na 3 AlF6), rau kev rwb thaiv tsev siab (SF6).
- Chlorine kuj pom muaj ntau yam kev siv. Nws yog siv los tua cov dej haus thiab cov pas dej da dej. Sodium hypochlorite (NaClO)yog qhov tseem ceeb ntawm cov tshuaj bleach. Hydrochloric acid yog dav siv hauv kev lag luam thiab chaw soj nstuam. Cov tshuaj chlorine muaj nyob rau hauv polyvinyl chloride (PVC) thiab lwm yam polymers uas yog siv los insulate xov hlau, kav, thiab electronics. Tsis tas li ntawd, chlorine tau ua pov thawj muaj txiaj ntsig zoo hauv kev lag luam tshuaj. Cov tshuaj uas muaj chlorine yog siv los kho kab mob, ua xua, thiab ntshav qab zib. Daim ntawv nruab nrab ntawm hydrochloride yog ib feem ntawm ntau yam tshuaj. Cov tshuaj chlorine kuj tseem siv los ua kom tsis muaj menyuam hauv tsev kho mob cov khoom siv thiab tshuaj tua kab mob. Hauv kev ua liaj ua teb, chlorine yog cov khoom xyaw hauv ntau cov tshuaj tua kab ua lag luam: DDT (dichlorodiphenyltrichloroethane) tau siv los ua cov tshuaj tua kab ua liaj ua teb, tab sis nws tsis siv lawm.
- Bromine, vim nws incombustibility, yog siv los suppress combustion. Nws kuj tseem pom muaj nyob hauv methyl bromide, tshuaj tua kab siv los khaws cov qoob loo thiab tua kab mob. Txawm li cas los xij, kev siv ntau dhau ntawm methyl bromide tau raug txiav tawm vim nws cov nyhuv ntawm ozone txheej. Bromine yog siv los ua cov roj av, cov duab thaij duab, tua hluav taws, tshuaj kho mob ntsws thiab Alzheimer's disease.
- Astatine yog cov xov tooj cua thiab tsis tshua muaj lub ntiaj teb halogen, yog li nws tseem tsis tau siv nyob qhov twg. Txawm li cas los xij, nws ntseeg tau tias lub ntsiab lus no tuaj yeem pab iodine hauv kev tswj hwm cov thyroid hormones.
Iodine ua lub luag haujlwm tseem ceeb hauv kev ua haujlwm ntawm cov thyroid caj pas. Yog tias lub cev tsis tau txais iodine txaus, cov thyroid caj pas loj. Txhawm rau tiv thaiv kab mob goiter, qhov halogen no ntxiv rau cov ntsev ntsev. Iodine kuj tseem siv los ua tshuaj tua kab mob. Iodine muaj nyob rau hauv cov tshuaj siv rauntxuav cov qhov txhab qhib, nrog rau cov tshuaj tua kab mob. Tsis tas li ntawd, nyiaj iodide yog qhov tseem ceeb hauv kev yees duab.
