Chng II

Chng III: H Thng Tun Hon Nguyn sn Bch

Chng III. H THNG TUN HON CC NGUYN T HA HCI. NH LUT TUN HON: 1) Mendeleev: Tnh cht cc nguyn t, thnh phn v tnh cht cc hp cht ca chng bin thin mt cch tun hon theo chiu tng dn khi lng nguyn t ca cc nguyn t.

Theo bng h thng tun hon hin i c mt s v tr khng ng :

39.95; 39.1. 58.93; 58.7. 127.6; 126.9 2) Theo c hc lng t: Tnh cht cc n cht cng nh dng v tnh cht ca cc hp cht ca nguyn t ph thuc tun hon vo chiu tng dn in tch ht nhn nguyn t ca cc nguyn t. II. BNG H THNG TUN HON CC NGUYN T HA HC

Hnh 3.1. Bng h thng tun hon

1. Cc h nguyn t s, p, d v f

a. Cc nguyn t h s

L cc nguyn t c electron cui cng in vo phn lp s ca lp ngoi cng. ns1: kim loi kim (IA) ns2: kim loi kim th (IIA)b. Cc nguyn t h pL cc nguyn t c electron cui cng in vo phn lp p ca lp ngoi cngnp1np2

np3

np4

np5

np6

IIIA

IVA

VA

VIA

VIIA

VIIIA

c. Cc nguyn t h dL cc nguyn t c electron cui cng in vo phn lp d ca lp k ngoi cng. ns2 (n 1)d1 10:u l kim loi chuyn tipd. Cc nguyn t h fL cc nguyn t c electron cui cng in vo phn lp f ca hai lp trc ngoi cng: ns2 (n 2)f 1 14: u l cc nguyn t t him.C 2 h nguyn t f : 6s2 4f 1 14: lantanid (CK6). 7s2 5f 1 14: actinid (CK7).2. Chu k

L dy cc nguyn t vit theo hng ngang sp xp theo chiu tng dn in tch ht nhn , bt u bng cc nguyn t h s, kt thc bng cc nguyn t h p, gia c th c (hoc khng) cc nguyn t h d, f.(tr CK1 ch c 2 nguyn t s) Trong mt chu k, tnh cht cc nguyn t bin i mt cch tun hon. S th t chu k bng s lng t chnh ca lp electron ngoi cng (n max), cng bng s lp e. C 7 chu k ( 3 CK nh v 4CK ln): -Chu k I: chu k c bit: ch c 2 nguyn t h s.-Chu k II, III: 2 chu k nh: mi chu k c 8 nguyn t, gm 2 nguyn t h s v 6 nguyn t h p.-Chu k IV, V: 2 chu k ln: mi chu k c 18 nguyn t, gm 2 nguyn t h s, 10 nguyn t h d v 6 nguyn t h p.-Chu k VI: chu k hon ho: c 32 nguyn t, gm 2 nguyn t h s, 14 nguyn t h f, 10 nguyn t h d v 6 nguyn t h p.-Chu k VII: chu k d dang: c 2 nguyn t h s, 14 nguyn t h f v mt s nguyn t h d(nu l 32 nguyn t). Nh vy bng HTTH nu s c tng cng (2+8+8+18+18+32+32 = 118 nguyn t) 2. Nhm: L ct dc cc nguyn t c s electron lp ngoi cng hoc cc phn lp ngoi cng ging nhau .C 3 loi phn nhm :a. Phn nhm chnh (A): Gm tt c nguyn t s v p c chu k nh v ln , mi phn nhm c 6-7 nguyn t nn ct cao. S th t phn nhm chnh bng tng s e 2 phn lp ngoi cng [ns np]:

IAIIAIIIAIVAVAVIAVIIAVIIIA

ns1ns2ns2np1ns2np2ns2np3ns2np4ns2np5ns2np6

b. Phn nhm ph (B): Gm tt c nguyn t h d, ch c chu k ln (4-7) nn ct thp. Mi phn nhm ph cha 3-4 nguyn t, ring PNP VIIIB c 9 ngt. c bit cha ton l kim loi chuyn tip. Trong mt chu k PNP bt u c nhm IIIB v phi sau 2 nguyn t s. S th t phn nhm ph c xc nh bi cu hnh e ca 2 phn lp cui :

Nhm IIIB: ns2(n 1)d1 Nhm IVB: ns2(n 1)d2 Nhm VB: ns2(n 1)d3 Nhm VIB: ns1(n- 1)d5 * Nhm VIIB: ns2(n 1)d5 Nhm VIIIB: ns2(n 1)d 6,7,8* Nhm IB: ns1(n 1)d10 * Nhm IIB: ns2(n 1)d10c. Phn nhm ph th cp (phn nhm ph ca phn nhm ph IIIB) PNP IIIB c 14 PNP th cp cha tt c cc nguyn t f , mi PNP th cp c 2 nguyn t f chu k 6,7 v c gi l cc nguyn t t him:

6s24f 1 14: lantanid. 7s25f 1 14: actinid.3. ng dng: Xc nh v tr cc nguyn t trong bng HTTH:a. Bit Z: TD: A1(Z = 19): 1s22s22p63s23p64s1 : CK4, PN IA , 19K . A2(Z = 25) : 1s22s22p63s23p64s23d5 : CK4, PN VIIB , 25Mn. A3(Z = 35) : 1s22s22p63s23p64s23d104p5 : CK4, PN VIIA , 35Br.b. Bit gi tr 4 s lng t ca electron cui cng:

TD: Nguyn t A4 c electron cui cng c gi tr 4 s lng t sau : n =3; =2; ml = 0; ms = - (qui c ml t - n + ):=> Phn lp cui cng: 3d8 : Ni (Z = 28): 1s22s22p63s23p64s23d8 (CK4, PN VIII B) ((((((((

m = -2 -1 0 +1 +2 c. Bit cu hnh electron ca ion tng ng:

Ion A2+: Phn lp cui cng l: 3p6.

=>A: 4s2 => CK4, PN IIA ( 20Ca). Ion D2+: Phn lp cui cng l: 3d5.=>D: 4s2 3d5 => CK4, PN VIIB (25Mn). Ion E3+: Phn lp cui cng l: 3d5.=>E: 4s2 3d6 => CK4, PN VIIIB (26Fe). Ion M4+: Phn lp cui cng l: 3p6.=>M: 4s23d2 => CK4, PN IVB (22Ti). Ion G4+ : Phn lp cui cng l: 4d10.=>G: 5s24d105p2 => CK5, PN IVA (50Sn). Ion X2-: Phn lp cui cng l: 4p6.=>X: 4s23d104p4 => CK4, PN VIA (34Se).d. Bit tng spin trong nguyn t:

TD: Nguyn t Q thuc chu k 4 c tng spin = +3.Q c (s = +3 => c 6 e c thn: 4s13d5 => CK4, PN VIB (24Cr).III. S THAY I TNH CHT CA CC NGUYN T TRONG BNG HTTH 1. Tng quan:

Tnh cht cc nguyn t ha hc trong HTTH thay i mt cch tun hon theo 3 chiu: ngang, dc v ng cho (khng quan trng):

Trong mt phn nhm: cu trc electron ha tr tng t nhau ( tnh cht ha hc tng t nhau. T trn xung di, do s lp electron tng ( lc ht ca ht nhn i vi e ngoi cng gim: tnh kim loi tng, tnh phi kim gim

tnh kh tng, tnh oxi ha gim

Trong mt chu k: t tri sang phi, s lp e khng thay i, tng s e lp ngoi cng tng ( lc ht ca ht nhn i vi e ngoi cng tng: tnh kim loi gim, tnh phi kim tng

tnh kh gim, tnh oxi ha tng 2. Bn knh nguyn t v ion* Coi nguyn t hay ion nh nhng hnh cu, hp cht l cc hnh cu tip xc nhau. Bn knh nguyn t hay ion c xc nh da trn khong cch gia cc ht nhn nguyn t to nn n cht hay hp cht tng ng (bn knh hiu dng R) * Bn knh hiu dng ph thuc:

bn cht nguyn t

c trng lin kt

trng thi tp hp

a.Bn knh nguyn t:*Trong mt chu k khi i t tri sang phi R nguyn t gim do Z tng trong chu k nh R gim r rt

trong chu k ln do e in vo lp k ngoi cng (n 1)d lm tng hiu ng chn ( R gim chm v u n hn*Trong mt phn nhm chnh, khi i t trn xung s lp e tng ( hiu ng chn tng ( R tng.

Hnh 3.4. Bin i bn knh nguyn t theo chu k v nhm.*Trong mt phn nhm ph, khi i t trn xung, xu hng chung: R tng nhng khng u n nh PNC:

-T CK4 xung CK5: R tng do tng thm mt lp e

-T CK5 xung CK6, CK7: R hu nh khng tng do hin tng co d, co f.b.Bn knh ion: R ( khi lc ht ca ht nhn i vi e ngoi cng ( M:lc ht i vi 1e ( . Nn:

R cation ( R nguyn t < R anion

i vi cation ca cng mt nguyn t: R gim theo chiu tng in tch ion

(R Fe2+ > R Fe3+ ; R Sn2+ > R Sn4+ ) i vi cc ion trong cng phn nhm c in tch ion ging nhau (cu trc e tng t nhau) R tng theo chiu tng in tch ht nhn Z

(R Li+ < R Na+ < R K+ < R Rb+ < R Cs+ ) ; (R F- < R Cl- < R Br- < R I-)

i vi cc ion ng e (cu trc e ging nhau) R ion gim theo chiu tng Z hay theo chiu tng s oxy ha.

(TD: R chui ion ng e c 10 e: N3- > O2- > F- > Na+ > Mg2+ > Al3+ )

Hnh 3.5 : Bn knh nguyn t v ion cc nguyn t phn nhm chnh. 4. Nng lng ion ha I: c trng cho kh nng nhng e ca nguyn t, th hin tnh kh hay tnh kim loi .

Hnh 3.5. Bin i nng lng ion ha Nng lng ion ha I l nng lng cn tiu tn tch mt e ra khi nguyn t th kh , c lp v khng b kch thch thnh cation tng ng th kh.

X(k) + I1 = X+(k) + e .

X+(k) + I2 = X2+(k) + e

I cng nh nguyn t cng d nhng e, do tnh kim loi v tnh kh cng mnh.

Trong mt chu k t tri sang phi nhn chung I tng dn do Z tng dn. Trong mt phn nhm chnh khi i t trn xung I gim do s lp e tng ( tng hiu ng chn.

Trong phn nhm ph khi i t trn xung, I tng.

Gii thch: PNP c c im: e c in vo phn lp d ca lp k ngoi cng, cn e lp ngoi cng ns2 khng thay i. Do :

+ Z tng rt nhanh ( tng lc ht ht nhn n e ns2 lp ngoi cng

+ Cc AO (n 1)d c tnh i xng khc hn AO ns nn hiu ng chn hu nh khng tng ( tng hiu ng xm nhp ca cc e s ca lp ngoi cng. Ngoi l:

+ Nu tch e ra khi mt cu hnh e ang bo ha th kh, I tng ln bt thng.

+ Ngc li, nu tch e xong t c cu hnh e bo ha th d, I gim.

TD: I1(IIA: ns2) > I1(IIIA: ns2 np1) ; I1(VA: ns2 np3) > I1(VIA: ns2 np4).

Cch tnh I1: I1 = E( - En max = 0 (eV) = eV.5.i lc electron F: c trng cho kh nng nhn e ca nguyn t , th hin tnh oxi ha hay tnh phi kim. Hnh 3.6. Bin i i lc electron

i lc e F l nng lng pht ra hay thu vo khi kt hp mt e vo nguyn t th kh, c lp, khng b kch thch thnh anion tng ng th kh.

X(k) + e = X-(k) ,F1 = (H F c gi tr cng m th nguyn t cng d nhn e, do tnh phi kim v tnh oxi ha ca nguyn t cng mnh.

i lc e ca X = nng lng ion ha ca X- nhng ngc du:

5. m in (( khi): c trng cho kh nng ht mt e v pha mnh khi to lin kt vi nguyn t ca nguyn t khc. Nguyn t ca nguyn t c m in ln hn s ht e v pha mnh khi tng tc vi nguyn t ca nguyn t khc c m in nh hn

C nhiu cch khc nhau xc nh m in. Trong mi chu k khi i t tri sang phi, nhn chung m in tng ln.

Trong mi nhm khi i t trn xung, m in gim.

* Ch : m in khng phi l i lng c nh ca mt nguyn t v n c xc nh trong s ph thuc vo thnh phn c th ca hp cht.

6. Ha tr v s oxi ha ca mt nguyn t: Ha tr ca mt nguyn t l s e ca mi nguyn t nguyn t b ra gp chung trong lin kt cng ha tr hay cho nhn trong lin kt ion. S oxi ha ca mt nguyn t l in tch hnh thc (khng phi in tch tht) ca mi nguyn t nguyn t khi qui c rng tt c lin kt xung quanh n u l lin kt ion bng cch cho nguyn t c m in ln hn ht e tch in m v ngc li. S oxi ha dng cao nht ca mt nguyn t = s th t nhm (tr cc nhm: I B, VIII B) S oxi ha m thp nht ca phi kim = s th t nhm - 8PAGE 12

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