M UDmitri Ivanovich Mendeleev (1834-1907) - cha ca Bng tun hon cc nguyn t ha hc, sinh ti thnh ph Tobolsk (Siberia), l nh ha hc, nh hot ng x hi, nh s phm ni ting nc Nga. Cng hin v i nht ca ng l nghin cu ra Bng h thng tun hon cc nguyn t ha hc (cn gi l Bng tun hon Mendeleev). y l mt cng hin xuyn thi i i vi lnh vc ha hc, l cha kha dn n s pht minh nhiu nguyn t ha hc mi, l kim ch nam cho nhng nghin cu trong ha hc ni chung. Ngi sau mnh danh ng l thn ca ca khoa hc Nga. L lun v quy lut tun hon cc nguyn t ca ng khng ch c th d kin v tr cho cc nguyn t cha tm ra m cn c th bit trc c tnh cht quan trng ca chng. Bng tun hon cc nguyn t ha hc ca Mendeleev tr thnh b sch gio khoa kinh in c th gii cng nhn. Mt nh khoa hc vit v ng: Trong lch s ha hc, ng dng mt ch n gin m gi ra c c th gii. nh lut tun hon v h thng tun hon l cng hin quan trng nht ca D.I.Mendeleev trong s pht trin khoa hc t nhin. Nhng ch l mt phn trong di sn sng to to ln ca nh bc hc. Ton b sng tc ca ng gm ti 25 tp sch. y l mt b bch khoa ton th thc th. Theo dng pht trin ca khoa hc v vi cc kim nh nghim tc trn c s nhng pht hin v i v nguyn t phng x v in t, cc nh khoa hc tng bc vch ra bn cht ca nh lut tun hon cc nguyn t ho hc. H da vo nhng ni dung hp l trong nh lut tun hon Mendeleev a ra nh lut tun hon mi, khoa hc hn so vi l lun ca ng. T gii quyt c vn m Mendeleev cn b ng. Tuy vy, chc chn mt iu rng khng ai c th ph nhn bng tun hon cc nguyn t ha hc ca Mendeleev l pht hin c tnh cch mng trong lnh vc ho hc.

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NI DUNG1.Vi nt v qu trnh xy dng nh lut tun hon v H thng tun hon: n gia th k XIX th gii tch ly c nhiu kin thc v ti liu thc nghim v cc nguyn t ha hc, trong c ln ln c ng c sai. n lc by gi c hn 60 nguyn t c tm ra, nhiu hp cht ha hc khc nhau c nghin cu, nhiu tnh cht c trng ca nguyn t, hp cht c thit lp Tuy nhin, s pht trin ca khoa hc k thut v cng nghip lc by gi i hi phi tip tc nghin cu v cc nguyn t v hp cht ca chng mt cch mnh m v c h thng. iu ny t ra cho cc nh ha hc vn h thng ha cc nguyn t nhm tm ra cc quy lut chung ni ln mi lin h gia chng vi nhau. Nhiu cng trnh nghin cu ra nhng cch phn loi nguyn t hoc tm ra mt s quy lut bin i tnh cht ca chng. Chng hn nh Berzelins phn chia cc nguyn t thnh kim loi, kim; Dobreiner sp xp nguyn t thnh tng b ba ging nhau, nh lut "bt " ca Newland, s bin i tun hon th tch nguyn t theo khi lng nguyn t ca Mayer... Tuy vy cc nh bc hc vn cha khm ph c thc cht ca nh lut tun hon. Trong qu trnh nghin cu v sp xp cc nguyn t, nh ha hc Nga Medeleev phn tch mt cch su sc mi quan h gia khi lng nguyn t vi nhng tnh cht l, ha hc, c bit l ha tr ca chng. ng nhn thy c s bin i tun hon nhng tnh cht theo chiu tng ca khi lng nguyn t. Nm 1869, Mendeleev cng b nh lut tun hon v th hin nh lut di dng mt bng: Bng tun hon cc nguyn t ha hc hay gi l H thng tun hon. H thng tun hon khng ch l s sp xp gin n cc nguyn t theo tnh cht ha hc v mt s tnh cht vt l ca chng, m n th hin mt trong nhng nh lut c bn ca t nhin. V vy va mi ra i xong n t ra l mt cng c sc bn trong vic nghin cu ha hc v mt s ngnh khoa hc khc. Da vo bng tun hon, Mendeleev sa li khi lng nguyn t ca khong 1/3 s nguyn t bit lc by gi, tin on s tn ti ca 11 nguyn t lc by gi cn cha bit, trong s ng d on y tnh cht ca 3 nguyn t, t lu sau ngi ta tm ra ba nguyn t l Sc, Ga, Ge vi nhng tnh cht ph hp mt cch k l vi d on ca Mendeleev. nh lut tun hon c mi ngi tha nhn.2

2. nh lut tun hon: 2.1. nh lut tun hon ca Mendeleev (giai on ha hc): nh lut tun hon c Mendeleev pht biu nh sau: Tnh cht ca cc nguyn t cng nh tnh cht ca cc n cht v hp cht cu to nn t nguyn t , ph thuc tun hon vo khi lng nguyn t ca chng. Thc cht ca nh lut l: Nu sp xp cc nguyn t theo chiu tng dn ca khi lng nguyn t, th qua mt s nguyn t nht nh c s lp li nhng tnh cht ha hc c bn (chu k lp li). Nh vy tnh cht ha hc ca nguyn t l hm s tun hon vi khi lng nguyn t ca chng. Nhng nu ly chiu tng dn ca khi lng nguyn t lm nguyn tc sp xp th trong mt s trng hp, m bo s tun hon phi i v tr ca mt s nguyn t, chng hn Co v Ni, Te v I... v nh vy, phi vi phm nguyn tc trn. S nguyn t t him v v tr ca chng trong h thng tun hon cng cha c xc nh mt cch dt khot. R rng trong cu to ni ti ca nguyn t c iu g gy nn hin tng tun hon m da vo khi lng nguyn t khng gii p c. 2.2. nh lut tun hon hin i (giai on electron): Bc tin quan trng trong vic gii quyt vn nu trn l tm c phng php xc nh in tch ht nhn nguyn t. T cc nh khoa hc kt lun: in tch ht nhn nguyn t, v tr s s hc bng s th t ca nguyn t trong bng h thng tun hon. Nh vy, cc nguyn t trong h thng tun hon c sp xp theo chiu tng dn ca in tch ht nhn nguyn t, ng thi l s th t ca nguyn t trong h thng tun hon. Mi nguyn t ng vi mt in tch ht nhn xc nh, n quy nh s e trong lp v nguyn t trung ha v chnh lp v e ny quy nh tnh cht ha hc ca nguyn t. Ngy nay nhn loi bit nhiu dng nguyn t c in tch ht nhn nh nhau, khi lng khc nhau nhng vn c tnh cht tng t nhau (hin tng l cc ng v). Vd: Cl c hai ng v l 35Cl v 37Cl. Ngc li, ngi ta cng bit c nhiu dng nguyn t c khi lng nguyn t nh nhau nhng do in tch ht nhn khc nhau nn dn n tnh cht ha hc khc nhau (hin tng l cc ng lng). Vd: Ra v As3

T m ngy nay nh lut tun hon c pht biu nh sau: Tnh cht ca cc n cht cng nh tnh cht cc dng hp cht ca nhng nguyn t ph thuc tun hon vo in tch ht nhn nguyn t ca cc nguyn t. Gia khi lng nguyn t v in tch ht nhn nguyn t c mi lin h cht ch vi nhau. Khi in tch ht nhn tng (s proton tng) th khi lng trung bnh ca cc ng v ca mt nguyn t cng tng (tc l tng khi lng nguyn t). Nhng v trong ht nhn nguyn t, s proton v notron khng thay i theo mt t l nht nh nn mt s t trng hp s thay i khi lng nguyn t khng theo cng trt t vi s thay i in tch ht nhn. nh lut tun hon hin i khng ph nh m tri li cn khng nh v chnh xc ha nh lut tun hon do Mendeleev khi xng. 2.3. nh lut tun hon di dng mi (giai on ht nhn): S khm ph ra cu to ht nhn nguyn t v mi lin quan c tnh quy lut gia cu to vi cc tnh cht ca ht nhn c th pht biu nh lut tun hon di dng mi, su sc v tng qut hn nh sau: Cc c tnh ca nguyn t, n cht, hp cht cng nh ca ht nhn cc nguyn t thay i tun hon theo chiu tng s nuclon trong ht nhn v electron trong lp v nguyn t ca cc nguyn t. Nh vy, nh lut tun hon dng mi ch ra mi lin h c tnh quy lut khng nhng gia cc nguyn t vi nhau m cn gia cc thnh phn ca chng l lp v e v ht nhn nguyn t. S pht trin hc thuyt cu to nguyn t cho php m rng tnh cht tun hon so vi giai on Mendeleev cho php pht hin hng lot hp cht v c khc nhau c tnh cht v iu kin to thnh c xc nh bi v tr ca cc nguyn t trong h thng tun hon (cc hydrua, cacbua, nitrua, borua, sunfua, kim loi, phc cht, kh tr). T nhng thnh tu mi ny da trn c s nh lut tun hon v H thng tun hon ngi ta thit lp hng trm h thng tun hon khc nhau khng nhng i vi cc tiu phn nh nguyn t, phn t, ion, ht nhn v cc electron m cn i vi tnh cht ca chng na. Ni tm li, ngy nay nh lut tun hon v h thng tun hon cc nguyn t tr thnh c s cho h thng ha ha hc.

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3.Cu trc h thng tun hon di nh sng cu to nguyn t: 3.1.Nguyn tc sp xp cc nguyn t trong bng tun hon: Ngy nay, di nh sng ca thuyt cu to nguyn t, cc nguyn t ha hc c sp xp trong bn tun hon theo cc nguyn tc: -Cc nguyn t c sp xp theo chiu tng dn ca in tch ht nhn nguyn t. -Cc nguyn t c cng s lp electron trong nguyn t c xp thnh mt hng. -Cc nguyn t c s electron ha tr(1) trong nguyn t nh nhau c xp thnh mt ct. Bng cc nguyn t c sp xp theo cc nguyn tc trn c gi l bng tun hon cc nguyn t ha hc (gi tt l bng tun hon). 3.2.Cu to ca bng tun hon cc nguyn t ha hc: 3.2.1. nguyn t: Mi nguyn t ha hc c xp vo mt ca bng, gi l nguyn t. S th t ca nguyn t ng bng s hiu nguyn t ca nguyn t . V d: Nhm (Al) chim 13 trong bng tun hon, vy s hiu nguyn t ca nguyn t Al l 13, s n v in tch ht nhn l 13, trong ht nhn c 13 proton v v nguyn t ca Al c 13 electron. 3.2.2.Chu k: Chu k l dy cc nguyn t ca chng c cng s lp electron, c xp theo chiu in tch ht nhn tng dn. Chu k thng bt u bng mt kim loi kim v kt thc bng mt kh him (tr chu k 1 v chu k 7 cha hon thnh). S th t ca chu k bng s lp electron trong nguyn t. 3.2.3.Nhm: Nhm gm cc nguyn t c s electron lp ngoi cng hoc ca nhng phn lp ngoi cng ging nhau v bng s th t ca nhm. Ni cch khc, cc nguyn t trong cng 1 nhm c cu hnh electron lp ngoi cng ging nhau, trong tng s electron ca cc phn lp ngoi cng lun bng s th t ca nhm. Mt s nguyn t nh Co, Ni c s electron ngoi cng ln hn 8 nhng vn t vo nhm VIII.5

Cc nguyn t h Lantanit v Actinit c cu to c bit, chng c t vo nhm VIII v c cc electron ang v xy dng phn lp (n-2)f nhng c t nhm III cng vi lantan (La) v actini (Ac). 3.2.4.Phn nhm: Phn nhm gm cc nguyn t c cu trc electron lp ngoi cng hoc ca nhng phn lp ngoi cng ging nhau. Phn nhm chnh gm cc nguyn t s hoc p c cu hnh electron lp ngoi cng tng ng l nsx hoc ns2npx-2 .Chng lun c s electron ngoi cng bng s nhm (x l s th t phn nhm). Phn nhm ph gm cc nguyn t d c cu hnh electron cc phn lp ngoi cng l (n-1)dx-2ns2 ( c mt s ngoi l Cu, Ag, Au c cu hnh (n-1)d10ns1). Phn nhm ph th cp gm cc nguyn t f c cu hnh electron lp ngoi cng l (n-2)f2-14(n-1)d0-1ns2 + Ghi ch: Cc nguyn t Zn, Cd, Hg c cu hnh electron l d10 chng khng c coi l nguyn t chuyn tip cng khng phi l kim loi in hnh.

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4.Cc kiu bng tun hon: Cho n ngy nay, ngi ta c gng rt nhiu trong vic hon thin cch biu din nh lut tin hon v cng b trn 500 kiu bng khc nhau. Ta s xt qua c im ca mt s kiu bng ph bin v tm hiu k v 2 dng ph bin nht l dng chu k ngn v dng chu k di. 4.1.Bng tun hon dng chu k ngn:C H U K Y

H A N GI II

NHOM CAC NGUYEN TO IIA IB

IIIIA IIB

IIIIIIB IIIA

IVIVB IVA

VVB VA

VIVIB VIA

VIIVIIB VIIA

VIIIVIIIB VIIIA

1 2 3 4 5

(H) Li Be Mg Ca Cu Rb Ag Ba Au Fr Ra Hg Ac Sr Cd La Tl Ku Zn Y In Hf Pb Ns Sc Ga Zr Sn Ta Bi B Al Ti Ge Nb Sb W Po C Si V As Mo Te Re N P Cr Se Tc O S Mn

H F Cl Fe Br Ru I Os At Ir Pt Rh Pd Co Ni

He Ne Ar

III Na IV V VI VII K

Kr

Xe

6 7

VIII Cs IX X

Rn

OXIT CAO NHAT HYDRUA

R2O

RO

R2O3

RO2 RH4

R2O5 RH3 Gd Cm

RO3 RH2 Tb Bk

R2O7 RH Dy Cf

RO4

LANTANIT

Ce Th

Pr Pa

Nd U

Pm Np

Sm Pu

Eu Am

Ho Es

Er Fm

Tm Md

Yb No

Lu Lr

ACTINIT

4.1.1.Nhm - Phn nhm: Cc nguyn t c b tr thnh 8 ct dc,c s th t t I n VIII. Trong mi nhm c chia thnh phn nhm chnh v phn nhm ph, to nn 2 hng dc . Cc phn nhm chnh gm nhng nguyn t in hnh ca nhm, c bt u t nguyn t nm chu k II , to thnh nhng ct dc di hn. Cc phn nhm ph gm nhng nguyn t hp thnh ct dc ngn hn c bt u bng nguyn t nm chu k IV. Ring Phn nhm ph c 14 phn nhm ph th cp to bi nhng nguyn t cng vi nguyn t La(Z=57) v Ac(Z=89). Chng thng c t thnh 2 dy nm ring 7

cui bng v c tn gi cc nguyn t Lantanit v Actinit. Mi phn nhm ph th cp gm mt nguyn t Lantanit v mt nguyn t Actinit. 4.1.2.Chu k: c b tr thnh hng ngang v c s th t t 1 n 7. Chng bt u t kim loi kim v kt thc bng nguyn t kh him.( tr chu k 1)

3 chu k u l chu k nh, trong chu k 1 l chu k c bit ch 2 nguyn t, chu k 2 v 3 u c 8 nguyn t chng u l nhng nguyn t in hnh v vy l nhng chu k in hnh

4 chu k sau l chu k di. Trong

- Chu k 4 v 5 c 18 nguyn t, trong c 8 nguyn t in hnh lm thnh 1 hng ngang v 10 nguyn t phn nhm ph (nguyn t chuyn tip) lm thnh mt hng ngang th 2 - Chu k 6 c 32 nguyn t (8 nguyn t in hnh, 10 nguyn t chuyn tip v 14 nguyn t h lantanit), chng c b tr trn 3 hng ngang (c 1 hng ngang ca h lantanit ngoi bng chnh) - Chu k 7: v l thuyt c 32 nguyn t nhng hin nay cha y (ch c 19 nguyn t) gm 2 nguyn t phn nhm chnh, 3 nguyn t chuyn tip v 14 nguyn t nhm actinit. y l chu k d dang. Nhiu tc gi cho rng dng ngn c nhiu u im: -Phn nh tt nht mi mi lin h quan trng nht gia cc nguyn t. -Nu ln c s tun hon ni ti trong mt chu k. -S phn chia phn nhm ph v chnh nu ln c s khc nhau v tnh cht gia cc nguyn t ca cc phn nhm nhng cng nu ln c s ging nhau v s oxi ha ca chng th bng vi s nhm. Tuy vy, mt s tc gi cho rng dng ngn vn cn thiu st: -Cc Lantanit v Actinit trn thc t b t ra ngoi h thng chung v khng cho thy mi lin h hu c vi cc nguyn t khc trong h thng. -Khng phn nh c s pht trin lin tc trong mt chu k (i vi cc chu k ln). -Khng nu c y mc lin quan gia cc nguyn t trong cng mt nhm.

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4.2. Bng tun hon dng chu k di:

KL kim KL kim th Halogen

Kh tr wefasr arttttrtr trttrhi m

KL chuyn tip

4.2.1.Nhm - Phn nhm: Cc nguyn t c electron cui cng in vo phn lp s ca lp ngoi cng gi l nguyn t nhm s. + Cu hnh ns1 : cc kim loi kim + Cu hnh ns2 : cc kim loi kim th Cc nguyn t c electron cui cng in vo phn lp p ca lp ngoi cng gi l cc nguyn t nhm p. Vy, nhng nguyn t m trong nguyn t, electron cui cng in vo phn mc s hoc p ca lp lng t ngoi cng th hp thnh nhng nguyn t thuc phn nhm chnh ( hay nhm A) : L nhng nguyn t in hnh. Cc nguyn t c electron tip theo in vo phn lp d ca lp trc ngoi cng gi l cc nguyn t nhm d. nhng nguyn t ny hp thnh nhng phn nhm ph loi 1 (n-1)d1-10ns2 (nguyn t kim loi chuyn tip). Cc nguyn t m trong nguyn t ,electron tip theo in vo phn mc f ca lp trc ngoi cng 2 lp gi l cc nguyn t nhm f. Nhng nguyn t ny hp thnh phn nhm ph loi 2 (h Lantanit: 4f1-145d0-106s2 v h Actinit: 5f1-146d0-107s2).9

Cc nguyn t d v f l cc nguyn t thuc phn nhm ph (hay nhm B). 4.2.2.Chu k: H thng tun hon c tri theo hng ngang, mi chu k by gi ch c 1 hng, v cc h nguyn t s,p,d,f c sp xp lin tc nhau. Do vy m cc phn nhm nguyn t c tch hn thnh nhng ct ring, trong phn nhm chnh c k hiu l A, phn nhm ph k hiu l B. +Chu k 1: cc electron sp xp vo lp K(n=1) trn phn lp s. H (Z=1) : He (Z=2) : 1s1 1s2

+Chu k 2: cc electron b sung th 3,4 tr i s c tip tc phn b vo lp mi L(n=2). u tin vo 2s, sau khi s vo phn lp 2p. Li (Z=3) Be (Z=4) B (Z=5)

1s2 2s1 1s2 2s2 1s2 2s2 2p1 1s2 2s2 2p6

Ne (Z=10)

+Chu k 3: tng t chu k 2,cc electron b sung t th 11 n 18 s tip tc phn b vo lp mi M(n=3), u tin vo 3s, sau n 3p. Khc vi lp L, lp ny phn lp 3d cn t do. Na (Z=11) Mg (Z=12) . Ar (Z=18) 1s2 2s2 2p6 3s2 3p6 Qua vic phn tch cu trc electron ca 3 chu k nh, chng ta thy: C sang chu k mi th electron b sung li c tip tc sp xp vo lp lng t mi c s lng t chnh n bng s th t chu k. +Chu k 4: K (Z=19) Ca (Z=20) Cr (Z=24) 1s2 2s2 2p6 3s2 3p6 3d5 4s110

1s2 2s2 2p2 3s1 1s2 2s2 2p6 3s2

1s2 2s2 2p6 3s2 3p6 4s1 1s2 2s2 2p6 3s2 3p6 4s2

Cu (Z=29)

1s1 2s2 2p6 3s2 3p6 3d10 4s1 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s1 1s2 2s2 2p2 3s2 3p6 3d10 4s2 4p6 5s2 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d5 5s1 1s2 2s2 2p6 30s2 3p6 3d10 4s2 4p6 4d10 5s1 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4s2 4p6 4d10 5s2 5p6 6s1 4s2 4p10 4d10 5s2 5p6 6s2 4s2 4p10 4d10 5s2 5p6 5d1 6s2 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 [Rn] 7s1 [Rn] 7s2

Kr (Z=36) Rb (Z=37) Sr (Z=38)

+Chu k 5:

Mo (Z=42)

Ag (Z=47) Xe (Z=54) Cs (Z=55) Ba (Z=56) La (Z=57) Rn (Z=86) Fr (Z=87) Ra (Z=88)

+Chu k 6:

+Chu k 7: cha hon thin.

Ns (Z=105) [Rn] 5f14 6d3 7s2 Ta thy c nhng nguyn t khng theo quy lut v d nh: Cr (Z=24) 3d5 4s1 thay v 3d4 4s2 Mo (Z=42) 4d5 5s1 thay v 4d4 5s2 (Theo quy tc bn bo ha) Cu (Z=29) 3d10 4s1 thay v 3d9 4s2 Ag (Z=47) 4d10 5s1 thay v 4d9 5s2(

Theo quy tc bo ha)11

La (Z=57) : electron c xp vo phn nhm 5d thay v 4f v mc nng lng ca n thp hn (quy tc Kleshkovski II) Nhn xt : Qu trnh hnh thnh lp v electron ca nguyn t cc nguyn t c tnh cht tun hon .C sau mt dy nguyn t li bt du xy dng lp electron mi. Dy nguyn t trong ang bt u xy dng mt lp electron mi gi l chu k Chu k gm nhng nguyn t m nguyn t ca chng c cng s lp electron tc l c cng tr s n. S th t chu k ng vi s lp electron. u chu k cc nguyn t bt u xy dng phn lp ns, cui chu k cc nguyn t kt thc vic xy dng phn lp np. 4.3.Bng tun hon dng thp: Dng ny khc phc c ng k nhng thiu st nu i vi cc dng k trn. V dng ny c 2 kiu ng ch : +Kiu bng do N.Bo cng b, kiu ny bao gm mt cch t nhin cc h Lantanit v Actinit. +Kiu bng do Necraxop hon thin t kiu bng ca Bo. u im ca n l phn bit c hai loi ng ng electron: -ng ng ton phn: nhng nguyn t m kin trc lp e ngoi cng ng nht bt c ha tr no.Vd: trong nhm V: N v P; As, Sb v Bi; V, Nb v Ta l nhng ng ng ton phn. -ng ng khng ton phn: nhng nguyn t m kin trc e lp ngoi cng ch ng nht mt vi ha tr ring bit. Vd: N v P ch ng ng vi V, Nb, Ta ha tr dng cao nht. N v P ch ng ng vi As, Sb, Bi cc ha tr -3 ; 0 ; +3. Cc dng chu k di c nhng u im nh nu trn. Tuy nhin cng c s kin cho rng vic xp cc nguyn t trong mt chu k di cng mt hang l san bng v tr ca chng trong h thng tun hon v vic in e vo cc phn lp trong nguyn t khng din ra lin tc v u n nh vy.

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4.4. Bng tun hon dng vng: Cc dng trn cha phn nh c s pht trin bin chng ca h thng tun hon cha gii quyt n tha c vic sp xp cc nguyn t hydro v cc b ba nguyn t trong nhm VIII. khc phc, mt s tc gi ngh biu din h thng tun hon theo dng vng. c im: Cc vng trn ng tm tng ng vi cc lp e khc nhau. H thng cc vng trn to nn cc chu k. Cc nguyn t trong nhm c phn b theo cc bn knh. Cc ch s rp ch cc chu k, s La M ch cc nhm. Cc Lantan c phn b vo tt c cc nhm tr nhm I v II, do tr nhm I v II ra mi nhm c 3 phn nhm. H thng ny c u im: -Phn nh c cu to cc lp lectron s, p, d, f trong nguyn t cc nguyn t. -C chu k n cc ng ng electron (ton phn v khng ton phn). -Sp xp c n tha v tr ca hydro (c nhm I v VII). Tuy nhin n vn tn ti mt s nhc im: -Tt c cc nguyn t trong mt chu k c phn b trn mt vng trn, n khng th hin c s bin i tnh cht gia cc nguyn t t kim loi in hnh n cc kim in hnh v kt thc l kh tr. -Ton b h thng ny rt khng cn i, phc tp, kh theo di. mt na vng trn tp trung hu ht cc nguyn t t nhm I n VII, cn na kia ch gm cc nguyn t nhm VIII.

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4.5.Bng tun hon dng xoy c: Dng xoy c ra i nhm khc phc nhng im yu ca dng vng. H thng ny c nhng c im: -Hydro c xp vo tm ca hnh xoy c vi ngha tt c cc nguyn t u c xy dng nn t cc ht c bn (electron, proton, notron) v hydro l nguyn t c bn nht. Trong h thng, hydro c coi l nguyn t tng ng vi cc nguyn t nhm I v VII. -ng xoy c c chia thnh 8 khu vc, mi nhm nguyn t c chia thnh 1 khu vc. -Mi nhm nguyn t gm 2 phn nhm chnh v ph. -Cc Lantanit v Actinit c coi l cc nguyn t thuc phn nhm ph nhm III. -Trong nhm VIII, cc nguyn t thuc phn nhm chnh l cc kh tr, thuc phn nhm ph l cc b ba Fe, Co, Ni ; Ru, Rh, Pd ; Os, Ir, Pt. - nhm IV tnh cht ca cc nguyn t thuc phn nhm chnh v ph ging nhau nhiu nht. Cng xa nhm IV v pha nhm I v VIII, tnh cht ca cc nguyn t thuc hai phn nhm cng khc nhau. iu c th hin bng nhng gc khc nhau gia cc bn knh trn sp xp cc nguyn t ca hai nhm. -Tt c cc nguyn t trong h thng c sp xp trn nhng ng xoy c, iu phn nh tnh cht bin chng ca nh lut tun hon. Cui mi chu k v bt u mt chu k mi c s chuyn ln mt vng mi. Cch biu din nh lut tun hon theo dng xoy c c nhiu u im, n th hin mt cch kh y v ng n nh lut tun hon. Tuy vy trn thc t dng ny khng ph bin nhiu v t thun tin. *Nhn chung, cc dng k trn u c th s dng biu din nh lut tun hon. Mi dng u c nhng u im ring v nhng thiu st ring. Nhiu kin cho rng dng ngn kinh in l dng hon ho nht tuy vn c nhng thiu st nht nh. N l mt mu mc v tnh h thng, n phn nh mt cch su sc mi mi

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lin h quan trng nht ca cc nguyn t, v hnh thc dng ny li cn i, gn nh, v d s dng. c bit trong cng tc ging dy th dng ngn t ra c thun li hn c. *Ngoi ra cn c Bng tun hon cc ht nhn nguyn t: S d c kiu bng l v cc dng nu trn khng p ng c yu cu ca ha hc ht nhn: +Chng khng cho php tin on nhng ng v cha tm thy cng nh m t trng thi, s lin quan gia cc ng v. +Chng khng cho thy s ph thuc tnh cht cc nguyn t vo cu to ht nhn m ch mi nu ln c s ph thuc vo in tch ht nhn. V vy cc nh ha hc ht nhn xy dng mt h thng tun hon cc ht nhn nguyn t. H thng ny rt phc tp v n bao gm hng nghn ht nhn v vn cha hon thin v cn nhiu ng v cha tm ra. Tuy vy, n cng c tc dng hu ch l c th tin on cc ng v cn cha bit. 5.S phn loi cc nguyn t: Da vo cu hnh electron c th chia nguyn t thnh 4 loi: -Cc kh tr. -Cc nguyn t in hnh. -Cc nguyn t chuyn tip. -Cc nguyn t h Lantanit v Actinit. 5.1.Kh tr: Nguyn t ca chng c cu hnh electron ns2 np6 ( tr He : 1s2). cc nguyn t ny tt c cc lp electron u bo ha hoc gi bo ha.S gi bo ha xy ra khi c 8 hoc c 18 electron nhng lp M , N, O, P (nu l bo ha th lp M phi c 18 electron, lp N: 32 electron, lp O:50 electron). Tt c cc electron u nm cc phn lp y , cc electron ngoi cng l electron s v electron p y . V vy chng kh tham gia phn ng ha hc hn cc nguyn t khc. Cho n nay cha tm thy hp cht bn ca cc kh tr nh nh heli, argon. Trong tt c cc trng thi tp hp, chng tn ti dng nguyn t ring bit v to thnh rt t hp cht ha hc. Cc lc tc dng gia cc nguyn t kh tr rt yu v khng nh hng (lc khuch tn, lc Vanevan). V vy cc kh tr c nhit nng chy v nhit si thp, cc tinh th c sp xp c kht nht.15

5.2.Cc nguyn t in hnh: cc nguyn t ny, tt c cc lp electron u bo ha hoc gi bo ha, tr lp ngoi cng c cu hnh t ns1 n ns2 np5. Tnh cht ha hc ca cc nguyn t loi ny ch yu ph thuc vo khuynh hng thu hay nhng electron c cu hnh electron. Thuc loi ny gm cc kim loi mnh v tt c cc kim. +Cc kim loi mnh nguyn t ca chng c t 1 n 3 electron bn ngoi cu hnh tr v c kh nng to thnh cc cation n c cu hnh tr. Nhng ion ny thng khng mu v nghch t. Cc nguyn t ny rt t c khuynh hng to thnh lin kt cng ha tr. Ha tr ca chng thng khng thay i hoc t thay i. l cc kim loi kim, kim th, cc nguyn t IIIA (tr Bo). +Cc kim gm cc nguyn t c t 4 n 7 electron lp ngoi cng. Chng c th to thnh cc lin kt cng ha tr v chnh nhng lin kt l c trng cho tng tc ha hc ca chng. i vi a s cc nguyn t loi ny cng c th to thnh cc anion n nhng hu ht cc anion ny ch c th tn ti trng thi rn (tr cc halogenua). Mt s nguyn t nng nht trong khu vc ny ca h thng tun hon thc ra l nhng kim loi do kh nng mt i N-2 electron (N l s nhm) to thnh cation. Tuy vy chng cng c th to thnh cc lin kt cng ha tr khi s dng tt c cc electron bn ngoi. Vic tch cc electron ra khi nguyn t ngy cng kh khn khi s th t ca nhm tng ln, v vy ng phn chia ranh gii ca kim loi v kim chy dc theo ng cho ca h thng tun hon t Bo n Te (tht ra khng c ranh gii dt khot gia kim loi v kim). 5.3.Cc nguyn t chuyn tip: Gm nhng nguyn t c hai lp e ngoi cha y , trong phn lp n-1 ng vi cu hnh (n-1)d1->9. Theo trn th c 4 dy nguyn t chuyn tip ng vi cc phn lp 3d, 4d, 5d v 6d (cha y ). Cc dy bt u t cc nguyn t phn nhm IIIB (Sc, Y, La, Ac) v kt thc bng cc nguyn t Ni, Pd, Pt. Tuy vy, ngi ta thng xp cc nguyn t: Cu, Ag, Au; Zn, Cd, Hg vo loi cc nguyn t chuyn tip do tnh cht vt l v ha hc c nhiu im ging vi cc nguyn t .16

Nh vy, ngi ta thng xp bn dy nguyn t chuyn tip sau: Sc____________Zn Y____________Cd La____________Hg Ac____________... Tt c cc nguyn t chuyn tip u thuc cc phn nhm ph loi mt gm 33 nguyn t. Tt c u l kim loi c nhit nng chy, nhit si cao hn cc kim loi thuc phn nhm chnh. Cc nguyn t chuyn tip v c phn lp (n-1)d cha y nn gy ra mt s tnh cht c trng so vi cc nguyn t thuc phn nhm chnh: -C nhiu trng thi ha tr do c s thay i tnh cht axit-baz, c tnh cht oxi ha kh ca cc hp cht trong mt gii hn rng ri. -Hp cht thng c tnh thun t. -Hp cht thng c mu. -Cc n cht v hp cht thng c tnh xc tc. -C nhiu kh nng to phc cht. 5.4.Cc Lantanit v Actinit: Cc nguyn t thuc h Lantan v Actini c ba lp electron bn ngoi cha y , trong c phn lp (n-2)f. Nhn chung, nguyn t ca cc nguyn t ny c cu hnh electron (n-2)f1-14 (n-1)d1 hoc 0 ns2. Chng to thnh cc cation v cc hp cht cng ha tr trong nguyn t c hai phn lp (n-1)d v (n-2)f cha y . Thuc loi ny c hai dy nguyn t: -14 nguyn t h Lantan. -14 nguynt h Actini. Tt c cc Lantanit u cho cc cation ha tr 3, to thnh cc mui bn v v nhiu mt (hu nh tt c) ging vi cc mui tng ng ca Sc v Y. Trong s cc c tnh ca h ny th c tnh ch yu l c ha tr bt thng i vi nguyn t u, gia v cui dy; (Ce, Tb c ha tr 4 bn; Eu, Yb c ha tr 2 bn). Cng ging nh cc nguyn t chuyn tip v cng do cc nguyn nhn tng t, cc Lantanit cho cc ion c mu v thun t.

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Tnh chtca ccLantanit rt ging nhau, cu hnh electron ca 14 nguyn t trong h ch khc nhau phn lp 4f. V d: Ce. Pr. Nd. Pm. ... Yb. . 4f14.... Phn lp (n-2)f lp th 3 k t ngoi vo nn t nh hng n tnh cht ca cc nguyn t trong h. Tnh cht ca cc Actinit cng tng t nh cc Lantanit nhng phc tp hn. V nhiu mt, Th tng t nh Ce nhng nhng nguyn t tip sau t Pa -> Am th hin nhng c tnh m khng c nguyn t no trong h thng tun hon c c. Tuy nhin n Cm th tnh cht ca n li rt ging vi Gd, v cc nguyn t tip theo li ging rt nhiu vi cc Lantanit tng ng. Ht *Ti liu tham kho: [1] nh lut tun hon v H thng tun hon Nh xut bn gio dc. [2] Cng ng ha hc H2VN - http://community.h2vn.com 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f2 5s2 5p6 6s2 . 4f3... . 4f4... . 4f5......

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MC LCM u Ni dung 1.Vi nt v qu trnh xy dng nh lut tun hon v H thng tun hon_______1 2. nh lut tun hon ____________________________________________________2 2.1. nh lut tun hon ca Mendeleev (giai on ha hc) 2.2. nh lut tun hon hin i (giai on electron) 2.3. nh lut tun hon di dng mi (giai on ht nhn) 3.Cu trc h thng tun hon di nh sng cu to nguyn t_________________ 4 3.1.Nguyn tc sp xp cc nguyn t trong bng tun hon 3.2.Cu to ca bng tun hon cc nguyn t ha hc 3.2.1. nguyn t 3.2.2.Chu k 3.2.3.Nhm 3.2.4.Phn nhm 4.Cc kiu bng tun hon_________________________________________________6 4.1.Bng tun hon dng chu k ngn 4.1.1.Nhm - Phn nhm 4.1.2.Chu k 4.2. Bng tun hon dng chu k di 4.2.1.Nhm - Phn nhm 4.2.2.Chu k 4.3.Bng tun hon dng thp 4.4. Bng tun hon dng vng 4.5.Bng tun hon dng xoy c 5.S phn loi cc nguyn t______________________________________________ 14 5.1.Kh tr 5.2.Cc nguyn t in hnh 5.3.Cc nguyn t chuyn tip 5.4.Cc Lantanit v Actinit19