pagpapakilala
grupo: 7 or VII B
Atomic Timbang: 98
panahon: 5
CAS Number: 7440-26-8
pag-uuri
No Stable Isotopes
matatag
likido
Gas
matatag (Nahulaang)
paglalarawan • Paggamit / Function
Element 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium. The element was actually discovered by Perrier and Segre in Italy in 1937. It was found in a sample of molybdenum, which was bombarded by deuterons in the Berkeley cyclotron, and which E. Lawrence sent to these investigators. Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial materials have been made without success. If it does exist, the concentration must be very small. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars. Thirty one isotopes and isomers of technetium, with atomic masses ranging from 86 to 113, are known. 97Tc has a half-life of 2.6 X 10^6 years. 98Tc has a half-life of 4.2 X 10^6 years. The isomeric isotope 95mTc, with a half-life of 61 days, is useful for tracer work, as it produces energetic gamma rays. Technetium metal has been produced in kilogram quantities. The metal was first prepared by passing hydrogen gas at 1100°C over Tc2S7. It is now conveniently prepared by the reduction of ammonium pertechnetate with hydrogen. Technetium is a silvery-gray metal that tarnishes slowly in moist air. Until 1960, technetium was available only in small amounts and the price was as high as $2800/g. It is now commercially available to holders of O.R.N.L. permits at a price of $74/g plus packing charges. The chemistry of technetium is said to be similar to that of rhenium. Technetium dissolves in nitric acid, aqua regia, and conc. sulfuric acid, but is not soluble in hydrochloric acid of any strength. The element is a remarkable corrosion inhibitor for steel. It is reported that mild carbon steels may be effectively protected by as little as 55 ppm of KTcO4 in aerated distilled water at temperatures up to 250°C. This corrosion protection is limited to closed systems, since technetium is radioactive and must be confined. 99Tc has a specific activity of 6.2 X 10^8 Bq/g. Activity of this level must not be allowed to spread. 99Tc is a contamination hazard and should be handled in a glove box. The metal is an excellent superconductor at 11 K and below. 1
pisikal na Katangian
Temperatura ng pagkatunaw:2* 2157 °C = 2430.15 K = 3914.6 °F
Electron Configuration: [Kr] 5s2 4d5
n = 4
electronegativity (Pauling scale):4 2.10
Tukoy Heat:
panlabas na Links:
Magazines:
(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:30-4:31.
Punto ng pag-kulo:2* 4265 °C = 4538.15 K = 7709 °F
pangingimbabaw Point:2
triple Point:2
Critical Point:2
densidad:3 11 g/cm3
* - at 1 atm
Electron Configuration
bloke: d
Pinakamataas Sinasakupan Level Energy: 5
valence electron:
quantum Numbers:
ℓ = 2
mℓ = 2
ms = +½
bonding
Electropositivity (Pauling scale): 1.9
Electron Affinity:5 0.55 eV
oksihenasyon States: +7,4,6
ionization Potensyal
eV 6
kJ/mol
1
7.28
702.4
ionization Potensyal
eV 6
kJ/mol
2
15.26
1472.4
ionization Potensyal
eV 6
kJ/mol
3
29.54
2850.2
termokimika
thermal kondaktibiti: 50.6 (W/m)/K, 27°C 7
Heat ng Fusion: 24 kJ/mol 8 = 244.9 J/g
Heat ng paggawa ng usok: 660 kJ/mol 9 = 6734.7 J/g
State of Matter
Entalpya ng Formation (ΔHf°)10
entropy (S°)10
Gibbs Libreng Enerhiya (ΔGf°)10
(kcal/mol)
(kJ/mol)
(cal/K)
(J/K)
(kcal/mol)
(kJ/mol)
(s)
0
0
8.00
33.472
0
0
isotopes
nuclide
masa 11
Half-Life 11
nuclear Spin 11
Binding Energy
100Tc
99.9076578(24)
15.8(1) s
1+
860.12 MeV
101Tc
100.907315(26)
14.22(1) min
9/2+
874.71 MeV
102Tc
101.909215(10)
5.28(15) s
1+
882.78 MeV
103Tc
102.909181(11)
54.2(8) s
5/2+
890.85 MeV
104Tc
103.91145(5)
18.3(3) min
(3+)#
889.61 MeV
105Tc
104.91166(6)
7.6(1) min
(3/2-)
897.68 MeV
106Tc
105.914358(14)
35.6(6) s
(1,2)
905.75 MeV
107Tc
106.91508(16)
21.2(2) s
(3/2-)
913.82 MeV
108Tc
107.91846(14)
5.17(7) s
(2)+
921.89 MeV
109Tc
108.91998(10)
860(40) ms
3/2-#
929.97 MeV
110Tc
109.92382(8)
0.92(3) s
(2+)
928.72 MeV
111Tc
110.92569(12)
290(20) ms
3/2-#
936.79 MeV
112Tc
111.92915(13)
290(20) ms
2+#
944.86 MeV
113Tc
112.93159(32)#
170(20) ms
3/2-#
943.62 MeV
114Tc
113.93588(64)#
150(30) ms
2+#
951.69 MeV
115Tc
114.93869(75)#
100# ms [>300 ns]
3/2-#
959.76 MeV
116Tc
115.94337(75)#
90# ms [>300 ns]
2+#
958.52 MeV
117Tc
116.94648(75)#
40# ms [>300 ns]
3/2-#
966.59 MeV
118Tc
117.95148(97)#
30# ms [>300 ns]
2+#
965.35 MeV
85Tc
84.94883(43)#
<110 ns
1/2-#
700.86 MeV
86Tc
85.94288(32)#
55(6) ms
(0+)
714.52 MeV
87Tc
86.93653(32)#
2.18(16) s
1/2-#
728.18 MeV
88Tc
87.93268(22)#
5.8(2) s
(2,3)
739.98 MeV
89Tc
88.92717(22)#
12.8(9) s
(9/2+)
752.70 MeV
90Tc
89.92356(26)
8.7(2) s
1+
764.50 MeV
91Tc
90.91843(22)
3.14(2) min
(9/2)+
777.23 MeV
92Tc
91.915260(28)
4.25(15) min
(8)+
788.10 MeV
93Tc
92.910249(4)
2.75(5) h
9/2+
800.82 MeV
94Tc
93.909657(5)
293(1) min
7+
809.83 MeV
95Tc
94.907657(6)
20.0(1) h
9/2+
819.76 MeV
96Tc
95.907871(6)
4.28(7) d
7+
827.83 MeV
97Tc
96.906365(5)
2.6E+6 a
9/2+
836.84 MeV
98Tc
97.907216(4)
4.2(3)E+6 a
(6)+
843.98 MeV
99Tc
98.9062547(21)
2.111(12)E+5 a
9/2+
852.98 MeV
Values minarkahan # ang hindi pulos nagmula sa pang-eksperimentong data, ngunit hindi bababa sa bahagyang mula sistematikong uso. Spins na may mahinang assignment argumento ay nakapaloob sa panaklong. 11
kasaganaan
compounds
Impormasyong pangkaligtasan
Material Safety Data Sheet - ACI Alloys, Inc.
Para sa karagdagang impormasyon
American Elements
Chemical & Engineering News
Chemical Elements
ChemGlobe
Chemicool
Environmental Chemistry
(1) Raloff, Janet. Desperately Seeking Moly. Science News, September 26, 2009, pp 16-20.
Pinagmumulan
(2) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(4) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(5) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(10) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(11) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).