Thiết kế bài giảng hóa học nâng cao tập 2

CAO CU GlAc (Chu bien)

NHA XUAT BAN HA NOI


TS. CAO C U G I A C (Chu bign) - ThS. HO THANH THUY

THIET KE BAI GIANG

NflNQCflO-TilPHfll

NHA XUAT BAN H A NOI



ChiroTig 5

DAI CirONG VE KIM LOAI
Bai 19. KIM LOAI VA HQP KIM
A. MUC TIEU BAI HOC
1. Kiln thiPc
HS biit:
• Vi tri cua kim loai trong bang tuan hoan.
• Cau tao ciia nguyen ttr Icim loai.
• Kliai niem, tinh chat va ung dung cua hop kim.
HS hiiu:
• Nhirng tinh chat vat li va tinh chat hoa hpc cua kim loai, hop kim.
• Nguyen nhan gay ra tinh chSt vat li chung, tinh khu cua kim loai.
2. KT nang
• Ren luyen kT nang: Tu vi tri cua kim loai suy ra cau tao va tinh chSt.
• • D§n ra dugc nhiing phan ijng hoa hoc va thi nghiem hoa hoc chung minh

cho nhirng tinh chat cua kim loai.
• Ren luyen kT nang giai bai tap ve kim loai.
3. Tinh cam, thai do
Biet dugc nhiing tinh chat quy gia cua kim loai lam cho HS co y thuc bao ve va
su dung tiet kiem kim loai.
B. C H U A N B! CUA GV VA

HS

• GV: - Bang tuan hoan cac nguyen to hoa hgc.
- Chuan bi mgt so thi nghiem minh hoa cho tinh khir ciia kim loai.
- Dung cu: Ong nghiem ca nho, ong nho gigt, den c6n,...


- Hoa chat: + Cac kim loai: Al, Cu. Fe (dinh sit sach).
+ Cac dung djch: axit H2SO4 loang, H2SO4 dac, HNO3,
CUSO4
• HS: Xem truac noi dung bai hgc.
C. TI^N TRiNH DAY - HOC
Hogt dpng ciia GV

Hogt dpng cda HS
A - KIM LOAI
Hogt dpng 1

I. VI TRI CUA KIM LOAI TRONG BANG T U A N HOAN
GV chieu bang tuan hoan len man hinh HS: Quan sat, thao luan cho ket qua:
(hoac treo baag tuan hoan co to mau
cac nguyen to len bang) cho HS quan
sat.

Vi tri kim loai gom:
GV huong dan HS tim ra vi tri ciia kim
loai trong bang:

- Nhom IA dgn VIA (Nhom IA trir H
nhom IIIA tru B) va mgt phan nhom
- Kim loai la cac nguyen to co to mau IVA,VA, VIA.
vang a trong bang tuan hoan.
- Nhom IB dSn VIIIB.
- Phi kim la cac nguyen to co to mau - Hai ho Lantan va Actini.
tim a trong bang tuan hoan.
Yeu cau HS xac dinh vi tri cua kim
loai.
GV bo sung: Ngoai each xac dinh a
tren thi kim loai nam a:
- Khoi nguyen to s (trir H, He)
- Mgt so a khoi nguyen to p

HS thao luan cho ket qua:

- Toan bg khoi nguyen to d, f

- Kim loai chiem da so vi tri trong bang
tuan hoan.

GV yeu cau HS nit ra ket luan ve vi tri
ciia kim loai.

- Kim loai nam a phia duai ben trai ciia
bang tuan hoan.

Hogt dpng cua HS

Hogt dpng cua GV
Hogt dpng 2

II. TINH C H A T VAT LI
1. Tinh chat vat li chung
GV giai thieu: 0 dieu kien thuang. cac HS lang nghe
kim loai deu a trang thai ran (trir Hg),
CO tinh deo, dan dien, dan nhiet va co
anh kim.
Vay the nao la tinh deo, tinh dan dien,
tinh dan nhiet, anh kim va tai sao kim
loai CO cac tinh chat tren chung ta se
nghien cuu timg tinh chat cu the.
a) Tinh deo
GV yeu cau HS nghien cim SGK va
cho biet:

HS thao luan nhan xet va cho ket qua:

- The nao la tinh deo?

- Tinh deo ciia vdt lieu la tinh bi bien
dang khi chiu ap luc ben ngoai hoac
nhiet tac dung va van giu dugc trang thai
bien dang do khi thoi tac dung.

- Giai thich.

- Gidi thich: Kim loai co tinh deo la vi
cac ion duang trong mang tinh the kim
loai CO the trugt len nhau de dang ma
khong tach ra khoi nhau nha nhiing
electron tu do chuyen dgng dinh ket
chiing vai nhau.

e.e;©
©•©•©.
e:©'©
©:©.©
•: Electron tir do
® : Ion duang kim loai

©:©©!
i»j .

•

• r

r^.©.#


Hogt dpng cua GV

Hogt dpng cua HS

GV bo sung: Kim loai c6 tinh deo Ion
nhat la Ag sau do la Al, Cu....
b) Tinh ddn diin
GV yeu cau HS nghien cim SGK va
cho biet:
- The nao la tinh dan dien?

Tinh ddn diin la tinh chit cua vat lieu
khi gin vao 2 diu vat lieu mgt hieu dien
thg thi tao thanh dong chuyen dai co
huang cua electron tir cue am sang cue
duang.
Gidi thich: Do trong kim loai co cac
- Giai thich.
electron tir do, chuyen dgng tir do trong
mang tinh the, khi co hieu dien the lap
tiic cac electron tu do chuyen dgng
GV bo sung: Kirn loai dan dien tot thanh dong co huong tao ra dong dien.
nhat la Ag, sau do den Cu, Au, Al,
Fe....
c) Tinh ddn nhiet
GV yeu cau HS nghien cuu SGK va
cho biet:
- Th6 nao la tinh din nhiet?

Giai thich.

- Tinh ddn nhiet la tinh chat cua vat lieu
CO th6 truy6n nang lugng (nhiet) tir vi tri
nay den vi tri khac.

- Gidi thich: Do kim loai co mat cac
electron tu do trong mang tinh the.

Cac electron trong viing nhiet do cao co
dgng nang lan, chuyen dgng hon loan va
nhanh chong sang viing co nhiet do thap
han, truyen nang lugng cho cac ion
duang a viing nay nen nhiet lan truyen
GV b6 sung: Thuang caic kim loai dan dugc tir viing nay den viing khac trong
khdi kim loai.
dien tot cung dan nhiet tot.


Hogt dpng cua GV

Hogt dpng cua HS

d) Anh kim
GV yeu ciu HS nghien cuu SGK va HS thao luan cho ket qua:
cho bi^t:
- The nao la anh kim?

Anh kim la anh sang thu dugc khi kim
loai hap thu anh sang trang va phan xa ra
anh sang co buac song dac trung cho
timg kim loai
Gidi thich: Do cac dam may electron tudo trong tinh the kim loai hap thu phan
xa hau het nhirng tia sang nhin thay
dugc, do do kim loai co ve sang lap lanh
ggi la anh kim.

- Giai thich.

HS nhan xet: Tinh chdt vdt li chung ciia
GV huang dan HS ket luan vin de: kim logi gdy nen boi su cd mat ciia cdc
Nguyen nhan gay ra tinh chat vat li electron tu do cd mat trong tinh thi kim
logi.
chung ciia kim loai?
2. Tinh chat rieng
GV giai thieu: Ngoai cac tinh chat tren HS nghe giang.
kim loai con co mgt so tinh chat vat U
khac nhu: Tinh cung, khoi lugng
rieng, nhiet do nong chay, nhiet do soi.
a) Khdi luang riing
GV cho HS nghien cim SGK va yeu HS nghien cuu SGK va nhan xet
ciu HS cho biet sir bien doi cac tinh Khoi lugng rieng ciia cac kim loai khac
chit: Tinh cimg, kh6i lugng rieng, nhau ro ret nhu:
nhiet do nong chay, nhiet do soi.
- Ll (D = 0,5 gam/cm ) la kim loat nhe
nhat.
- Os (D = 22,6 gam/cm ) la kim loai
nang nhat.


Hogt dpng cua GV

Hogt dpng cda HS

b) Nhiet dp ndng chay
Nhiet do nong chay cua kim loai dao

dgng trong mgt khoang rgng nhu:
Kim loai co t°,thip nhit la Hg(-39"C)
Kim loai co t°,cao nhit la W(3410°C)
c) Tinh cirng
Tinh cicng ciia kim loai ciing rat khac
nhau nhu: Cr la kim loai cirng nhat, kim
loai ki6m thi rat mem co the dung dao de
cat.
Hogt dpng 3
II. TINH C H A T H O A H O C CHUNG CUA KIM LOAI
GV huong dan HS rut ra tinh chat hoa HS thao luan nhan xet cho ket qua sau:
hgc ca ban ciia kim loai:
- Kim loai thuang co it electron (l-3e)
- Dac diem cau tao cua nguyen tir kim a lop ngoai ciing.
loai (so electron hoa tri).
- Xu huang cho electron de dat dugc
- Du doan xu huang ciia kim loai de cau hinh ben.
CO dugc cau hinh ben cua khi hiem.
- Tinh chat chung cua kim loai la tinh
- Suy ra tinh chat chung cua kim loai. khir.
M

^M""+ne

Hogt dpng 4
\. Tac dun 5 vol phi kim
GV giai thieu: Kim loai co the tac HS thao luan cho ket qua:
dung vai nhieu phi kim a nhiet do cao. Kim loai tac dung vai phi kim tao thanh
Yeu cau HS cho biet san pham, lay vi muoi (trir oxi)
du minh hoa.

F/t/w.-2Fe +3C12 ^—> 2FeCl3
2A1 + 302 -^-^
Fe + S - ^ ^ FeS

2AI2O3


Hogt dpng cda GV

Hogt dpng cua HS
Hogt dpng 5

2. Tac dung voi dung dich axit
a) Ddi v&i dung djch HCl, H2SO4 hang
GV neu vin At. Cac dung dich axit HS thao luan de giai quyet van de:
HCl, H2SO4 loang co tinh oxi hoa.
Nhung tai sao chi tac dung dugc vai
cac kim loai dimg truac H trong day
hoat dgng?
San pham phan ung thu dugc la gi?
GV huang dan HS Giai quyet vin dh,
Viet cac phuang trinh hoa hgc minh
hoa

Cac phan tir axit HCl, H2SO4 loang co
tinh oxi hoa do ion H trong phan tir axit
the hien nen chi tac dung vai cac kim
loai CO tinh khir manh han hidro.
San pham phan img la muoi va H2.
Phuang trinh hoa hgc phan ung:

Zn +HC1 -> ZnCb + H 2 t

GV bo sung: Cac kim loai da hoa tri
thuang bi oxi hoa len so oxi hoa trung
binh nhu: Fe, Cr...

Fe —> Fe

Zn + H2S04 ^ ^

ZnS04+ H2T

+2

b) Ddi v&i, H2SO4 (dgc,ndng), HNO3
GV dat vin dk: Tai sao HNO3, H2SO4
dac lai tac diing dugc vai hau het cac
kim loai (trir Au, Pt) Trong khi axit
HCl, H2SO4 loang khong co dugc tinh
chat nhu vay?
GV huang dan HS giai quyet van de.

HS thao luan de giai quyet vin de duai
su huong dan ciia GV:
+ 1 +6-2

+1 +5 -2

- S6 oxi hoa cua cac nguyen to trong - So oxi hoa: H2 SO4, H N O3
phan til- axit ITNO3, H2SO4.

Hogt dpng cua GV

Hogt dpng ciia HS

- Kha nang oxi hoa cua cac nguyen t6.
- San pham ciia phan img.

+ 1 +5

+6

- Kha nang oxi hoa chi co H,N, S
nhung dg oxi hoa dugc cac kim loai yeu
+5

+«

nhu: Cu, Ag... thi chi co thd la N, S .
- San pham ciia su oxi hoa.
S la: SO2, S, H2S
N la: NO2, NO, N2O, N2, NH4NO3.
- Viet cac phucmg trinh phan img - Phuong trinh hoa hgc:
minh hoa.
3Cu + 8HNO3 -> 3Cu(N03)2 + 2 N 0 1
+ 4H2O
2Ag + 2H2SO4

'° > Ag2S04 + SO21

+ 2H2O

Fe+6HN03dac

GV nhan xet va bo sung:

'° > Fe(N03)3+ 3NO21

- Tuy vao dieu kien phan ung ma cho
ra cac san pham khir khac nhau.
- Thuang cac kim loai bi oxi hoa len
so oxi hoa cao.
- Axit FtN03 va H2SO4 dac, ngugi lam
thu dgng hoa Al, Fe, Cr...
Hogt dpng 6
3. Tac dung voi dung djch muoi
GV lam thi nghiem: Ngam 1 thanh sat HS quan sat va nhan xet
da (cao sach gi) vao dung dich CUSO4
loang sau 1 thai gian, cho HS quan sat
va yeu cau.

10

+ 3H2O


Hogt dpng cua HS

Hogt dpng cda GV
- Quan sat hien tugng.

- Hien tugng: dung dich CUSO4 nhat
mau dong thai tren thanh sat co Cu kim
loai mau do bam vao thanh sat.

- Giai thich.

- Gidi thich: Fe co tinh khir manh hon
Cu. Khir Cu^^ thanh Cu.
Nong do CUSO4 giam lam mau xanh
nhat dan, dong thai Cu kim loai mau do
tao ra bam len thanh sat.

- Viet phuang trinh hoa hgc minh hoa.

- Phuang trinh hoa hgc
Fe + CUSO4 -> FeS04 + Cu

GV lam tiep thi nghiem: Cho 1 mau

HS quan sat va nhan xet

Na vao dung dich CUSO4 loang Cho
HS quan sat va yeu cau:
- Quan sat hien tugng.

- Hiin tugng: Thay mau Na tan dan
dong thai c6 khi bay ra va dung dich
nhat mau, co ket tua mau xanh nhat xuat
hien.

- Gidi thich: Ban dau mau Na tac dung
- Giai thich bang phuong trinh hoa
vai nuac lam mau Na tan va co khi
hoc.
2Na + 2H2O -> 2NaOH + H21
Sau do NaOH trao doi vai CUSO4 tao
thanh ket tua Cu(0H)2
CuS04+2NaOH->Cu(OH)2 + Na2S04
GV yeu ciu HS so sanh 2 thi ng hiem
dh rut ra ket luan.

Kit ludn: Tuy vao ban chat kim loai ma
san pham tao ra la khac nhau.

GV khic sau kien thuc:

HS ghi bai.

Dieu kien kim loai tac dung vai dung
dich mu6i tao ra kim loai mai.

11


Hogt dpng cua GV

Hogt dpng cda HS

- Kim loai co tinh khir manh han kim

loai trong muoi.
- Kim loai khong tac dung vai nuac a
nhiet do thuong.
- Muoi cua kim loai tao ra phai tan.
GV bo sung ngoai cac tinh chit tren thi
kim loai con co cac phan img khac:

Phuang trinh hoa hgc

- Tdc dung vai oxit kim logi: Vi du Al

2A1 + Fe203 — ^

AI2O3 + 2Fe

tac dung dugc vai Fe203, Fe304, CuO.
- Tdc dung vdi oxit phi kim Vi du: Mg

Mg + CO2 - ^ ^ MgO + CO

CO the khu dugc CO2, SO2...
- Kim logi Al, Zn, Be... tdc dung vai 2Al+2NaOH+2H20-»2NaA102 + 3H2
dung dich baza.
Yeu cau HS viet phuong trinh hoa hgc
minh hoa.
Hogt dpng 7
4. Tac dung v6"i nu-dc
GV yeu cau HS viet cac kieu phan
img ciia kim loai ma HS da timg biSt?

HS viet phuang trinh hoa hgc
2Na + 2H2O -> 2NaOH + H21

GV thong bao: Vay nhirng kim loai
nao thi co phan ung theo kilu ciia Na,
theo kieu ciia Fe. Co the xet nhu sau:

Fe + H2O — i ^ FeO + H21
HS ghi bai.

- Cac kim loai nhom IA, IIA (trir Be,
Mg) CO tinh khir manh tac dung vai
nuac a nhiet do thuong tao ra bazo tan
va hidro.
- Cac kim loai co tinh khir yeu han tac
dung vai nuac o nhiet do cao tao ra
oxit kim loai va hidro.
12

J


Hogt dpng cda HS

Hogt dpng cda GV
- Cac kim loai co tinh khir rat yeu nhu
Ag, Au, Pt... thi khong cac dung dugc
vai nuac.
B - HOP KIM
Hogt dpng 8

I. DINH NGHIA

GV chieu len man hinh tranh anh hoac HS quan sat thao luan va nhan xet:
cac mau vat sau va giai thieu:
- Manh duyra la hgp kim cua Al, Cu,
Mn, Mg.
- Thanh thep (1 mieng gang) la hgp
kim ciia Fe, C.
- Day chuyen, nhan, bong tai lam
bing vang tay la hgp kim ciia Au, Cu,
Ag.
Yeu ciu HS cho biit: Thanh phan ciia
cac hgp kim tren c6 gi giong va khac

Gidng nhau: Deu co thanh phan la kim

nhau.

Khdc nhau: Ngoai kim loai do con c6
kim loai khac hay phi kim trong hgp

/
Tir do neu khai niem hgp kim.

loai.

kim.
Dinh nghia:

Hgp kim la vat lieu kim loai c6 chira mgt

kim loai ca ban va mgt so kim loai va
- Hgp kim khong phai la hon hgp
phi kim khac.
thong thuang thu dugc khi trgn 2 chit
vol nhau. Ma la san phim thu dugc khi
nung chay hon hgp kim loai vai kim
.loai hay kim loai vai phi kim.
GV bo sung:

- Hap kim c6 ciu tao tinh the va dugc
chia lam cac loai:

13


Hogt dpng cda GV

Hogt dpng cda HS

+ Tinh the hon hgp.
+ Tinh the dung dich ran.
+ Tinh the hgp chat hoa hgc.
Hogt dpng 9
II. TINH C H A T C U A H O P KIM
GV giai thieu:

HS nghe giang va ghi bai.

- Tinh chdt hod hoc cua hgp kim thi
thuang CO tinh chat ciia cac don chat

cau tao nen hgp kim.
Vi du: Hgp kim Cu-Zn thi co tinh chat
cua Cu va tinh chat cua Zn.
- Tinh chdt vdt li: Co nhiSu thay doi
so vai tinh chat cua cac dan chat.
GV neu cac vi du sau ve don chat va
hgp chat

HS thao luan va nhan xet.

- Vang 99,99% dep nhung mem, - Tinh cimg: Hgp kim thuang cung han
nhirng d6 diing bing vang 99,99% de cac kim loai thanh phan.
meo va mon. De khac phuc nhung
nhugc di§m do nguai ta diing hgp kim
ciia vang vai Ag, Cu de lam do trang
sire va due tien.
- Do dan dien cua Cu rit tot (dung thu - Do ddn dien ciia hgp kim giam nhieu
2, sau Ag). Do dan dien ciia dong giam so vai kim loai don chat.
nhanh n8u co lan tap chat. Do vay, day
dien la d6ng c6 do tinh khiet den
99,99%.
- Nhiet do nong chay ciia Sn (232 C)
Nhiet do nong chay ciia Pb (327,4 C)
-> Nhiet do nong chay cua hgp kim
Sn-Pb (thiec han) la 2 l o V
14

- Nhiet dp ndng chay cua hgp kim giam
so vai kim loai dan chat.

Hogt dpng cda HS

Hogt dpng cua GV
Yeu cau HS nhan xet sir biln d6i tinh
chat vat li ciia hgp kim.
Hogt dpng 10

III. inVG DUNG CUA HOP KIM
GV Chieu len man hinh tranh, hinh HS ghi bai
anh bang powerpoint giai thieu ve Thep khong gi (thep inox):
nhung ling dung cua hgp kim.
Fe(74%)-Ni(8%)-Cr(18%): Chd tao
dung cu y te, nha bep.
- Thep Mn rat ben, chiu dugc va dap
manh, dung de che tao duong ray xe lira,
may nghien da.
- Thep W-Mo-Cr rit cung dii a nhiet
do cao, diing ch8 tao luai dao cat ggt
kim loai cho may tien, may phay.
- Duyra hgp kim Al(95%), Cu(4%),
Mn-Mg-Si(l%). Duyra nhe gin nhu
nhom nhung lai rit cung, cimg gap 4 lan
nhom tuc gin bing thep ma lai nhe bang
1/3 thep. Duyra b6n. Diing lam vat lieu
ch6 tao may bay, 6 to.
Hogt dpng 11

CUNG CO BAI VA BAI TAP VE NHA
GV chidu cac bai tap sau len man hinh HS quan sat theo luan cho ket qua

cho HS thao luan cung c6 ngi dung bai
hgc:
Cau 1. Kim loai nao trong cac kim Cau 1. Chgn dap an D
loai sau tac dung dugc vai ca 4 dung
dich muoi: Zn(N03)2, AgN03, CuCb,
AICI3?
15


Hogt dpng cda GV
A. Fe

B. Al

C. Cu

D. Mg

Hogt dpng cua HS

Cau 2. Dot chay hoan toan 4,04 gam Cau 2. Chgn dap an D
hon hgp bot ba kim loai Cu, Al, Fe thu
dugc 5,96 gam hon hgp 3 oxit. DS hoa
tan het hon hgp ba oxit nay can V lit
dung dich HCl IM. Gia tri ciia V la
iCho 0=16. Al=27, Fe=56, Cu=64)
A. 0,12 lit.

B. 0,14 lit.

C O , Hit.

D.O, 24 lit

Cau 3. Nhom chat nao sau day deu tac
dung dugc vai dung dich NaOH?

Cau 3. Chgn dap an A

A. Al, Al203,NH4Cl, Si
B. Si. CI2, FeCh. N2
C. Si, CI2, S,N2
D. Al, Fe, Cu(N03)2, KHSO4
Bai tap ve nha: 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10, 11, 12 (SGK).

D. HU'ONG

D A N GIAI

BAI TAP TRONG SGK

1.

Chgn dap an B

2.

Chgn dap an C

3.

Chgn dap an C

4.

Dung.

5.

Vi tri ciia kim loai trong bang tuan hoan:
- Cac nguyen to s (nhom IA, IIA).
- Cac nguyen t6 d (nhom IIIB, IVB, VB, VIB, VIIB, VIIIB, IB, IIB).
- Cac nguyen to f (hg lantan va hg actini).
- Mot phin cac nguyen to p.

16


Vl tri kim loai co tinh khir manh nhat: Goc trai phia duoi bang, do la nguyen t6 Cs.
Vi tri phi kim co tinh oxi hoa manh nhit: Goc phai phia tren bang, do la
nguyen td F.
Cau hinh electron nguyen tir:
6.

F: 1 s^2s"2p'

Cau hinh electron nguyen tir va ion:
Thidu:

7.

Cs: [Xe]6s'

Na:lsV2p'3s'

Na": l s - 2 s V

Fe: [Ar] 3d'4s-

Fe"": [Ar] 3d'

Fe'": [Ar] 3d'

a) Truang hgp xay ra phan img
Fe + CUSO4 -^
Fe + Pb(N03)2 ^
Vai tro cac chat tham gia phan img
- Chat khir: Fe
- Chit oxi hoa: Cu^", Pb""
b) Phudng trinh hoa hgc dang ion thu ggn:
Fe + Cu^" -> Fe'" + Cu
Fe + Pb^" -^ Fe^" + Pb

8.

a)

Cu + Fe2(S04)3 ^ CUSO4 + 2FeS04
Cu + 2Fe'" ->

Cu"" + 2Fe^"

Fe + CUSO4 -^ Cu + FeS04
Fe + Cu"" -^ Fe-" + Cu
b) So sanh: Fe co tinh khir manh han Cu; Fe
Cu" ; Cu
9.

co tinh oxi hoa manh han

c6 tinh oxi hoa manh han Fe" .

a) Cho dung dich 2 muoi tac diing vai bgt Fe du. Phan img xong, Igc bo bgt
Fe du, nuoc lgc la dung djch FeS04.
HS viet phuang trinh hoa hgc
b) Ngam hon hgp bgt Cu, Zn, Pb trong dung dich Cu(N03)2 du. Sau phan
irng, lgc dugc chat ran la Cu.
HS viet phuang trinh hoa hgc.

2-TKBGHOAH
-| y


10. a) Zn + CUSO4 -^ Cu + ZnS64
Theo phuang trinh hoa hgc. cir 1 mol Zn (65g) bi hoa tan thi sinh ra 1 mol Cu
(64 g) bam tren kim loai Zn. Do vay kh6i lugng la Zn giam sau phan ung.
Ciing suy luan nhu vay ta c6 cac ket qua:
b) va c): Kh6i lugng la Zn tang sau phan img.
d) Khoi lugng la Zn giam sau phan irng.

11. Phuang trinh ion thu ggn:

Dat

M + Pb^" -^ M-" + Pb

(1)

M + Cu^" -> M^" + Cu

(2)

X (g) la kh6i lugng mol ciia kim loai M.
n la s6 mol kim loai M tham gia phan ung.
a la khdi lugng la kim loai M ban diu.

Theo (1) khi co nx (g) kim loai M tham gia phan irng, sinh ra 207n gam Pb.
Ta c6 phuang trinh dai so:
207-nx

Rutra:

100% = 19%
a
n(207-x)
a = -^--.100

/o^.
(3)

Theo (2) khi c6 nx (g) kim loai M tham gia phan img, sinh ra 64n gam Cu.
Ta CO phuong trinh dai so:
nx-64

-.100% = 9,6%

a
Rutra:

a=^ ^ ^ . 1 0 0
9,6

(4)

Tir (3) va (4), ta co:
il(207^100=i^^^^^.l00
19
9,6
Kim loai M co khdi lugng mol 112 la cadimi (Cd).
12. Giai tuong tu bai tap 8.
Kim loai M co khdi lugng mol 65 g/mol la Zn.

18

^x=112(g).


E. TU- LIEU THAM KHAO
De giai thich cac li tinh ca ban cua kim loai c6 the dua vao thuylt "khi
electron" va thuylt vimg ndng lugng.

1. Thuyet "khi electron"
Thuyet "khi electron" cho ring mang tinh the kim loai d thd rin va long bao
gom dong thdi cac nguyen tir da bi ion hoa, tire la cac nguyen tir da bi tach mgt
phan cac electron hoa tri cua minh. Cac electron hoa tri lien kit ylu vdi cac hat
nhan nguyen tir, trong do cd mgt s6 chuyin dgng tu do de dang trong toan khdi
kim loai, chuyen ddng hdn loan nhu cac phan tir khi. Vi thi c6 thi coi nhu cd
khi electron chuyin ddng trong mang tinh thi kim loai. Kilu lien kit giira "khi
electron" vdi cac nguyen tir va ion kim loai ggi la lien kit kim logi.
Gidi thich: Bang thuyet "khi electron" cd thi giai thich dinh tinh cac tinh chit li
hgc dac trung cua kim loai:
• Kim loai cd anh kim vi "khi electron" trong ciu triic tinh thi kim loai tao ra
cho kim loai kha nang phan chieu manh cac biic xa nhin thiy. Mgt sd kim
loai cd mau vi chi hap thu mdt sd birc xa va phan chilu mdt sd biic xa nhin
thay khac. Ddng cd mau do vi nd da hap thu cac biic xa ciing mau xanh.
• Kim loai dan dien tdt vi "khi electron"chuyln ddng tir hon loan sang cd
hudng khi lap mdt hieu dien thi d hai diu day din. Dun ndng, do dan dien
giam vi tang su chuyen dgng hdn loan ciia "khi electron" va tang sir dao
ddng cua nguyen tir hay ion kim loai lam can sir chuyin ddng cd hudng cua
electron.
• Kim loai dan nhiet tdt vi khi tang nhiet do d mdt cho thi d dd nguyen tir va
ion kim loai dao ddng manh, truyen sang cac electron tu do, rdi tir cac
electron tu do truyen sang cac nguyen tir va cac ion kim loai lan can... Cir
the dao ddng ciia cac nguyen tir va cac ion trong toan khdi kim loai dugc
tang cudng va trang thai nhiet cua khdi kim loai dugc thang bing nhanh chdng.
• Kim loai cd tinh deo la nhd "khi electron" lien kit cac tieu phan
(nguyen tir va ion kim loai) trong tinh the va chiing cd thi bi xe dich do
chiu tac dung cua mdt lire ca hgc.
Han che cua thuyet "khi electron" la khdng thi giai thich dugc mdt each triet
de mire do khac nhau ve 4 tinh chat li hgc dac trung cua kim loai va khdng thi
giai thich dugc cac tinh chat li hgc rieng cua mdi kim loai.

19


2. Thuyet vung nang luotig
Thuyet viing nang lugng dua tren co sd phuong phap obitan phan tir (MO), la
thuylt hien dai cd thi khic phuc nhirng thilu sdt cua thuyet "khi electron" ve
cau true kim loai.
Theo thuylt nay, kim loai rin hay ldng cd -cau true tinh the, nut mang la ion
duang. Cac obitan nguyen tir (AO) hoa tri ciia cac kim loai dugc td hgp thanh
cac MO chung cho toan bg tinh thi. Trong sir hinh thanh phan tir hai nguyen
tu. sir xen phii giira 2 AO lien kit lam xuit hien 2 MO. Khi mdt nguyen tir thu
ba dugc kit hgp vao phan tir nay thi cd sir hinh thanh 3 MO. Nhu vay neu tinh
thi kim loai gdm N nguyen tir (N = 6.023.10^'^) thi sir xen phu ciia N AO se
cho ta N (MO). Moi MO img vdi mdt trang thm nang lugng xac dinh. Vi so N
rit ldn. nen N trang thai xich lai gin nhau tao nen viing nang lugng. Su khac
nhau vl nang lugng ciia cac trang thai trong gidi han mdt vimg la vd ciing nhd
be. chi bing khoang 10"^^ eV, nen cd thi coi viing nang lugng nhu mdt vach
nang lugng lien tuc. Cac MO ciia vimg nang lugng tuong tu nhu cac MO bat
dinh xir khap tinh the kim loai.
Hinh 5.1 cho thiy sa dd hinh thanh cac mire nang lugng (tao ra viing nang
lugng khi tang sd nguyen tir tuang tac).
E

1

2

4

8

IG

N

Hinh 5.1. Sa 66 hinh thanh cac viing nang lugng khi tang lien tuc
so nguyen tu trong tinh the kinn loai

Su diln cac electron vao cac MO trong viing nang lugng xay ra theo thii tu
nang lugng tang din va theo nguyen li Pauli (mdi MO tdi da 2e cd spin ddi
song). Vay nlu tinh thi gom N nguyen tir, cac vimg nang lugng hinh thanh do
sir xen phii cac AO s, p, d, f se chiia toi da 2N (viing s), 6N (viing p), 1 ON
(vimg d) va 14N (vimg f) electron. Tuy thudc vao ciu hinh electron cua nguyen
tir va tinh ddi ximg ciia mang tinh thi, viing chiia electron dam bao cho sir lien
kit goi la viing hod tri (vimg chiia electron hoa tri) va viing trdng tren viing hoa
20


tri ggi la viing ddn. Neu viing hoa tri va viing dan khdng xen phu nhau thi cd
mdt khoang gian doan ve nang lugng ggi la vimg cdm. 0 cac tinh the kim loai
thudng xay ra sir xen phu nhau ciia viing hoa tri va viing dan. Trong chit ban
dan viing cam cd chilu rgng AE = 0,1 - 3,0 eV va trong chit dien mdi (each
dien) cd A E > 3,0 eV (xem hinh 5.2).

v'ung dan
Vung dan

Hoac
Vung
dan

Vung
hoa tri
Kim loai

Cac vung
pliu len
nhau

Vung dan

Vung cam re ng

Vung
hoa tri
Vat each dien

Viing cam hep
Vung
hoa tri

Vat ban dan

Hinh 5.2

Cac electron hoa tri chuyen ddng tren cac MO chung cho toan bd tinh thi nen
cd tac dung rang budc cac ion duong kim loai thanh mdt khdi.
Gidi thich tinh chdt vdi li cua kim logi:
• Theo thuyet viing nang lugng, vi cac electron hoa tri chuyen ddng tren eac
MO ciia viing hoa tri tao ra nhirng dam may electron da lam tang kha nang
phan chieu va giam kha nang hap thu cac buc xa nhin thay ma kim loai cd

anh kim. Cung vi cd cac electron hoa tri chuyen ddng tren cac MO chung
ma lam cho toan bd tinh the ludn ludn lien ket vdi ion duong thanh mdt khdi
ddu chiu dugc tac dung ciia luc ca hgc ma kim loai cd tinh deo.
• Tinh dan dien va dan nhiet tdt ciia kim loai dugc giai thich nhu sau: cac kim
loai dan dien tdt nhat thudc nhdm IA va IB. Nguyen tir cua cac kim loai nay
chi cd 1 electron hoa tri s nen vimg nang lugng cua tinh the kim loai mdi
chira 1/2 sd electron tdi da. Trong tinh the chira N nguyen tii' thi cd N (AOs)
ciia Idp ngoai cimg xen phii tao ra N (MO), lap thanh viing nang lugng gdm
N mire. Vi cd N electron hoa trj nen so electron chi chiem N/2 mire (moi
mire 2 electron). N/2 mire bi electron chiem tao thanh viing hoa tri. N/2 miic
21


con lai dang trdng tao thanh vimg dan. Cac miic bi chiem nam gan true tiep
vdi cac mire trdng tao co hdi cho cac electron cd the chuyen dich dugc duai
tac dung ciia dien trudng. Do dd kim loai nhdm IA va IB dan dien tot.
Trong tinh the kim loai nhdm IIA va IIB sir xen phu ciia cac AOs ciia N
nguyen tir ciing tao ra vimg N mire. Do mdi nguyen tir cd 2 electron s nen
\ung nay phai dugc xep 2N electron, nghia la viing hoa tri da dugc dien dii.
Tuy nhien, cac AOp ben ngoai ciing xen phu nhau thanh cac MO tao ra
vimg nang lugng trdng p vdi 3N mire (vimg dan). Hai viing hoa tri s va vimg
dan p xen phii nhau tao thanh viing lai hoa sp. Cac electron eiing chuyen
dich true tiep theo cac mire cua vimg lai hoa sp khi cd tac dung cua dien
trudng.
Tuang tu vdi cac nguyen td chuyen tiep d (chang ban Cr 3d 4s ). Neu tinh
thi gom N nguyen tir thi kit qua cua su xen phii ciia cac AOs ldp ngoai
cimg tao ra vimg s gdm N miic va cua AOd ldp sat ngoai ciing tao ra vimg d
gdm 5N mire. Su xen phii cua 2 viing s va d tao ra vimg lai hoa ds gdm 6N
mire. Nguyen tir ciia nguyen td chuyen tiep nhu Cr chi cd 6 electron hoa tri
nen tinh thi N nguyen tir chi cd 6N electron hoa tri va chi dien vao 6N/2 =

3N mire. Viing lai hoa ds cdn 3N miic trdng nen kim loai chuyen tiep dan
dien tdt.
Cac kim loai dan nhiet tdt nhd kha nang di chuyen tu do ciia cac electron
hoa tri trong tinh the va truyen nang lugng tir phan ndng hon sang phan lanh
hon. Khi dun ndng, dao ddng cua cac nguyen tir tai chd bi dun ndng trd nen
manh hon, gay khd khan cho su chuyen ddng cd hudng ciia electron hoa tri
tu do theo chieu ciia dien trudng hay tir phan ndng den phan lanh. Do do
tinh dan dien va dan nhiet ciia kim loai giam khi nhiet do tang.
Thuc nghiem cho thay khoang 1 electron trong sd cac electron hoa tri ciia
nguyen tir kim loai gay ra tinh dan dien va dan nhiet, sd electron hoa tri con
lai tham gia tao lien ket cdng hoa tri ben giira cac nguyen tir kim loai. Do do
phan ldn cac kim loai chuyen tiep cd khdi lugng rieng, nhiet do ndng chay,
nhiet do sdi va do cimg ldn hon nhieu so vdi cac kim loai khdng chuyen
tiep.

22


Bai 20. DAY DIEN HOA CUA KIM LOAI
A. MUC TIEU BAI HOC
1. Ki§n thii'c
HS biit:
• Cac khai niem: Cap oxi hoa - khir ciia kim loai, pin dien hoa, suit dien ddng
va the dien cue.
• Cau tao cua pin dien hoa, su chuyin dgng cua cac phin tir mang dien khi pin
dien hoa hoat ddng.
• Cac phan ung hoa hgc xay ra d catot (cue +) va anot (cue - ) ciia pin dien
hoa.
• The dien cue chuan ciia kim loai.
• Day the dien cue chuan cua kim loai va y nghTa cua nd.

HS hiiu:
• Cach sir dung day dien hoa de du doan chieu cua phan iing oxi hoa khir.
• Cach xac dinh suat dien ddng chuan ciia cap pin dien hoa.

2. KT nang
• So sanh tinh oxi hoa ciia cac ion kim loai, tinh khir ciia cac kim loai giira cac
cap oxi hoa - khir.
• Xac dinh ten va dau ciia cac dien cue trong pin dien hoa, tinh dugc suat dien
ddng cua pin dien hoa.
• Tinh dugc the dien cue chuan cua mdt sd cap oxi hoa - khir trong pin dien hoa.

3. Tinh cam, thai do
Van dung kien thiie da hgc de giai thich co che hoat ddng ciia pin, acquy
thudng diing trong cugc sdng hinh thanh tu duy logic cho HS.
B. C H U A N B! CUA GV VA

HS

• GV: - Lap rap mdt sd pin dien hoa Zn - Cu, Pb - Cu, Zn - Pb theo hinh
5.3 SGK
- Mdt sd tranh anh dugc ve trudc.
• HS: On lai bai cii va xem trudc bai hgc

23


C. TIEN TRINH DAY - HOC
Hogt dpng cua HS

Hogt dpng ciia GV

Hogt dpng 1

I. KHAI NIEM VE CAP OXI HOA - KHLT CUA KIM LOAI
GV yeu cau HS

HS thao luan cho ket qua

- Viet qua trinh nhudng, nhan electron
ciia cac kim loai va ion sau: Cu, Ag, Fe,
Ag", Cu-", Fe-".
- Cho biet vai trd ciia cac chat trong
ban phan irng.

4-

s.

Ag+e <
^-.

1+

Cu

^

+2e <

*

0

1 Ag
N.

./^

0

' Cu

he +2e < ' he
Chat oxi hoa
Chat khir

GV gidi thieu: Dang oxi hoa va dang
khir ciia cimg mdt nguyen td tao nen
cap oxi hoa-khii' ciia kim loai:
o-~ ,-^
Bieu dien:

D'ttsoxibda/
^
/u,, , , ..
/ D ' n g kho

Yeu cau HS viet eac cap oxi hoa- khir
cho cac nguyen td kim loai tren.
GV bd sung: Ngoai cap tren cdn mdt sd
cap dac biet nhu: ^^ / i, - ^ /i T

/re"
/ rt.

HS viet cac cap oxi hoa / khir:

AgV
/Ag -

cu^y
/Cu'

Fe-y
/Fe

Hogt dpng 2
II. PIN DIEN HOA
1. Khai niem ve pin dien hoa, suat dien dong va the dien circ
GV lam thi nghiem:

HS quan sat thi nghiem va nhan xet:

- Cdc 1 dung 50ml dung dich CUSO4 Hiin lugng:
IM cdc 2 dung 50ml dung dich ZnS04 - Kim vdn ke bi lech ve phia circ Cu cd
IM. hai cdc ndi vdi nhau bang dng chu gia tri 1,10V.
U cd chira KNO3 liim cau ndi.

- Dien cue Zn bi an mdn dan.

- Nhiing vao cdc CUSO4 1 la Cu, cdc - Cd 1 ldp kim loai Cu bam len dien
ZnS04 1 la Zn hai la kim loai nay dugc circ Cu.

24