các nguyên tố nhóm iia
TRANSCRIPT
Cc nguyn t nhm IIA
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Thnh vin
12 3 4 5
Nguyn Trung Hiung Tun Hng ng Duy Huy Gip Vn Thnh inh Vn Xun LOGO
Chng c gi l kim th v cc thuc tnh t nhin trung gian ca chng gia cc cht kim (xt ca cc kim loi
kim) v cc loi t him (xt ca cc kim loi t him) Cc kim loi kim th c t tn theo cc xt ca chng, cc t kim, c tn gi c l berilia, magisia , vi sng, strontia v baryta Trong lp v Tri t kim loi kim th chim t l 4,16 %
(trong y 67 % Canxi, 31 % Magi, 1,4 % Bari, 0,6 %Stronti v 1 lng rt t Berili v Radi)LOGO
Ni dung
12 3 4
Tnh cht n chtHp cht ha hc Nc cng ng dng v iu ch
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Nguyn t
Be
Mg
Ca
Sr
Ba
Ra
S hiu nguyn t
4
12
20
38
56
88
Nng lng 1800 ion ha I2 (kJ/mol) m in 1,57
1450
1150
1060
970
-
1,31
1,00
0,95
0,89
-
in th cc -1,85 chun EoM2+/M
-2,73
-2,87
-2,79
-2,90
-
Khi lng nguyn t
9
24
40
88
137
(226)
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1. Tnh cht n cht u c mu trng bc hoc xm nht, trong khng kh c Be v Mg gi c nh kim.
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Nguyn t
im nng chy (K)
im bc hi (K)
Khi lng ring (kg/m)
cng
dn in (S/m)
Bn knh nguyn t (nm)
Berili
1551,15
~2750
1848
5,5
31,3 . 106
0,113
Magi
923
1380
1738
2,5
22,6 . 106
0,160
Canxi
1115
1757
1550
1,75
29,8 . 106
0,197
Stronti
1050
1655
2630
1,5
7,62 .106
0,215
Bari Radi
1000 973
1913 2010
3620 5500
1,25 -
3 .106 -
0,217
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Tnh cht ha hc 1. Tc dng vi phi kim a. Tc dng vi H2: - Khi t cc kim loi kim th trong kh quyn H2 kh th Ca, Sr, Ba d dng to ra cc hp cht hirua kim loi.
- Phn ng : M + H2 MH2Khi tip xc vi H2O, cc hirua ny to thnh dung dch M(OH)2 v H2
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b. Tc dng vi oxi: - Khi t nng, tt c cc kim loi kim th u chy trong khng kh to ra oxit. 2M + O2 2MO - Tr BeO, tt c cc oxit ca kim loi kim th u tc dng vi nc cho dung dch baz
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c. Tc dng vi cc phi kim khc: - Khi ung nng cc kim loi kim th tc dng mnh lit vi cc phi kim mnh nh halogen, lu hunh, nit...to ra mui. M + X2 MX2 M + S MS 3M + N2 M3N2 - Cc nitrua kim loi kim th tc dng vi nc to ra
hiroxit v gii phng NH3
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2. Tc dng vi axit a. Tc dng vi HCl, H2SO4 long:
- kh d dng ion H+ ca dung dch axit (HCl, H2SO4 long) thnhH2 : M + 2H+ M2+ + H2 b.Tc dng vi dung dch axit HNO3, H2SO4 c: - Vi dung dch HNO3 long: cc kim loi nhm IIA c tnh kh mnh c th kh N+5 xung cc s oxi ho thp. V d: 4M + 10 HNO3 4M(NO3)2 + NH4NO3 + 3H2O - Vi HNO3 c : M + 4 HNO3 M(NO3)2 + 2NO2 + 2 H2O - Vi H2SO4 c, nng : M + 2 H2SO4 MSO4 + SO2 + 2 H2OLOGO
3. Tc dng vi H2O - Be khng tc dng vi H2O d nhit cao - Mg tc dng chm vi H2O nhit thng to ra Mg(OH)2, tc dng nhanh vi hi nc nhit cao to thnh MgO Mg + H2O hi MgO + H2 - Ca, Sr, Ba tc dng vi H2O nhit thng to thnh
dung dch baz.Ca + 2H2O Ca(OH)2 + H2LOGO
4. Tc dng vi dung dch baz - Ch c Be phn ng c vi dung dch baz to mui berilat v kh H2 - Phn ng : Be + 2Na(OH) + H2O =Na2[Be(OH) 4] + H2 (Be + 2NaOH Na2BeO2+ H2)
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2. Tnh cht hp cht Cc oxit MO: l cht rn mu trng, kh nng chy v rt bn nhit. Phn ng vi H2O, ta nhit. (Tr BeO)
Cc hydroxit M(OH)2 : Be(OH)2 v Mg(OH)2 t tan trong H2O. Be(OH)2 c tnh lng tnh. Be(OH) 2 + 2Na(OH) = Na2[Be(OH) 4] M(OH) 2 + 2HCl = MCl2 + 2H2O C kh nng hp th CO2
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Cc peoxit MO 2 : Be khng to c peoxit, Mg ch to c peoxit dng hydroxit c ln peoxit MgO2 v cc peoxit khc th
rt kh tan trong nc. CaO2 : Ca(OH)2 + H2O2 + H2O2 = CaO2.8H2O CaO2.8H2O CaO2 + 8H2O BaO2 c iu ch bng cch sc khng kh qua BaO 600C : BaO + 0,5O2 BaO2
SrO2 cng c iu ch nh vyv p sut c125 atm Cc peoxit c kh nng tan trong axit to ra H2O2
.
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Cc mui halogen: l cht rn trng, d tan, ht m mnh Cc mui sunfat o Canxi oxalat (CaC2O4) l thnh phn chnh ca si thn o Canxi cacbua (CaC2) dng trong cng nghip sn xut Axetilen ,
kh Lu hunh t kim loi th, ...o Canxi cyanamit (CaCN2) dng lm phn bn
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Berili xt BeO
Magi MgO
Canxi CaO
Stronti SrO
Bari BaO
Hirxt
Be(OH)2
Mg(OH)2
Ca(OH)2
Sr(OH)2
Ba(OH)2
Florua
BeF2
MgF2
CaF2
SrF2
BaF2
CloruaSulfat
BeCl2BeSO4
MgCl2MgSO4
CaCl2CaSO4
SrCl2SrSO4
BaCl2BaSO4
Cacbonat
BeCO3
MgCO3
CaCO3
SrCO3
BaCO3
Nitrat
Be(NO3)2
Mg(NO3)2
Ca(NO3)2
Sr(NO3)2
Ba(NO3)2
Sulfua
BeS
MgS
CaS
SrS
BaS LOGO
3. Nc cng Nc cng l loi nc t nhin cha trn 3 milimol lg cation canxi (Ca2+) v magie (Mg2+) trong mt lt. Nc cha
nhiu Mg2+ c v ng. Tng hm lng ion Ca2+ v Mg2+ ctrng cho tnh cht cng ca nc. cng ca nc thin nhin dao ng rt nhiu v c trng ln nc ngm.
C 2 loi cng ca nc cng: cng tm thi v cngvnh cu Mm ha nc cng bng cch cho kt ta Mg2+ v Ca2+ vi (Na2CO3), photphat hoc tch chng bng nha trao i ion hoc un si.LOGO
4. ng dng v iu cha. ng dng ca kim loi kim th: Kim loi Be c lm cht ph gia ch to nhng hp kim c tnh n hi cao, bn chc, khng b n mn... Kim loi Mg c dung ch to nhng hp kim c c tnh
cng, nh, bn...Bt Mg trn vi cht oxi ho dng ch tocht chiu sng ban m. Kim loi Ca dung lm cht kh tch oxi , lu hunh ra khi thp, CaO c ng dng rng ri trong cng nghip sx xi mng.LOGO
b.
iu ch cc kim loi kim th: - Nguyn tc: Kh ion kim loi kim th: M2+ + 2e M - Phng php: in phn nng chy mui ca chng
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