RADÃO

Introdução

Número atômico: 86
Grupo: 18 or VIII A
Peso atômico: 222
Período: 6
Número CAS: 10043-92-2

Classificação

Calcogênio
halogênio
Gás nobre
Lantanóides
Actinóide
Terra-rara
Platinum Metal Group
Transuranium
Não Isótopos Estáveis
Sólido
Líquido
Gás
Sólido (previsto)

Descrição • Usos / Função

The element was discovered in 1900 by Dorn, who called it radium emanation. In 1908 Ramsay and Gray, who named it niton, isolated the element and determined its density, finding it to be the heaviest known gas. It is essentially inert and occupies the last place in the zero group of gases in the Periodic Table. Since 1923, it has been called radon. Thirty nine isotopes and isomers are known. Radon- 222, coming from radium, has a half-life of 3.823 days and is an alpha emitter; Radon-220, emanating naturally from thorium and called thoron, has a half-life of 55.6 s and is also an alpha emitter. Radon-219 emanates from actinium and is called actinon. It has a half-life of 3.96 s and is also on alpha emitter. It is estimated that every square mile of soil to a depth of 6 inch contains about 1 g of radium, which releases radon in tiny amounts to the atmosphere. Radon is present in some spring waters, such as those at Hot Springs, Arkansas. On the average, one part of radon is present to 1 X 10^21 part of air. At ordinary temperatures radon is a colorless gas; when cooled below the freezing point, radon exhibits a brilliant phosphorescence which becomes yellow as the temperature is lowered and orange-red at the temperature of liquid air. It has been reported that fluorine reacts with radon, forming radon fluoride. Radon clathrates have also been reported. Radon is still produced for therapeutic use by a few hospitals by pumping it from a radium source and sealing it in minute tubes, called seeds or needles, for application to patients. This practice has now been largely discontinued as hospitals can order the seeds directly from suppliers, who make up the seeds with the desired activity for the day of use. Radon is available at a cost of about $4/millicurie. Care must be taken in handling radon, as with other radioactive materials. The main hazard is from inhalation of the element and its solid daughters, which are collected on dust in the air. Good ventilation should be provided where radium, thorium, or actinium is stored to prevent build-up of this element. Radon build-up is a health consideration in uranium mines. Recently radon build-up in homes has been a concern. Many deaths from lung cancer are caused by radon exposure. In the U.S. it is recommended that remedial action be taken if the air in homes exceeds 4 picocuries/L. 1

• "radiotherapy of cancerous tissues" 2

Propriedades físicas

Ponto de fusão:3*  -71 °C = 202.15 K = -95.8 °F
Ponto de ebulição:3* -61.7 °C = 211.45 K = -79.06 °F
Ponto de sublimação:3 
Ponto Triplo:3 
Ponto crítico:3 104 °C = 377.15 K = 219.2 °F 3
Densidade:4  9.074 g/L

* - at 1 atm

Configuração Electron

Configuração Electron: [Xe] 6s2 4f14 5d10 6p6
Quadra: p
Mais alto nível de energia Ocupado: 6
Elétrons de valência: 8

Números quânticos:

n = 6
ℓ = 1
m = 1
ms = -½

Colagem

Electron Affinity:5 not stable eV
oxidação Unidos: 0

potencial de ionização   eV 6  kJ/mol  
potencial de ionização   eV 6  kJ/mol  
potencial de ionização   eV 6  kJ/mol  
1 10.7485    1037.1

Termoquímica

Calor específico: 0.094 J/g°C 7 = 20.868 J/mol°C = 0.022 cal/g°C = 4.988 cal/mol°C
Condutividade térmica: 0.00364 (W/m)/K, 27°C 8
Calor de fusão: 2.89 kJ/mol 9 = 13.0 J/g
Calor da vaporização: 16.4 kJ/mol 10 = 73.9 J/g
Estado da matéria Entalpia de formação (ΔHf°)11 entropia (S°)11 Gibbs Energia Livre (ΔGf°)11
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(g) 0 0 42.09 176.10456 0 0

isótopos

nuclide Massa 12 Meia vida 12 spin nuclear 12 Energia de ligação
195Rn 195.00544(5) 6 ms 3/2-# 1,506.62 MeV
196Rn 196.002115(16) 4.7(11) ms [4.4(+13-9) ms] 0+ 1,514.69 MeV
197Rn 197.00158(7) 66(16) ms [65(+25-14) ms] 3/2-# 1,522.77 MeV
198Rn 197.998679(14) 65(3) ms 0+ 1,540.15 MeV
199Rn 198.99837(7) 620(30) ms 3/2-# 1,548.22 MeV
200Rn 199.995699(14) 0.96(3) s 0+ 1,556.29 MeV
201Rn 200.99563(8) 7.0(4) s (3/2-) 1,564.37 MeV
202Rn 201.993263(19) 9.94(18) s 0+ 1,572.44 MeV
203Rn 202.993387(25) 44.2(16) s (3/2-) 1,580.51 MeV
204Rn 203.991429(16) 1.17(18) min 0+ 1,588.58 MeV
205Rn 204.99172(5) 170(4) s 5/2- 1,596.65 MeV
206Rn 205.990214(16) 5.67(17) min 0+ 1,604.72 MeV
207Rn 206.990734(28) 9.25(17) min 5/2- 1,612.79 MeV
208Rn 207.989642(12) 24.35(14) min 0+ 1,630.18 MeV
209Rn 208.990415(21) 28.5(10) min 5/2- 1,628.94 MeV
210Rn 209.989696(9) 2.4(1) h 0+ 1,646.32 MeV
211Rn 210.990601(7) 14.6(2) h 1/2- 1,645.08 MeV
212Rn 211.990704(3) 23.9(12) min 0+ 1,653.15 MeV
213Rn 212.993883(6) 19.5(1) ms (9/2+) 1,661.22 MeV
214Rn 213.995363(10) 0.27(2) μs 0+ 1,669.29 MeV
215Rn 214.998745(8) 2.30(10) μs 9/2+ 1,677.36 MeV
216Rn 216.000274(8) 45(5) μs 0+ 1,676.12 MeV
217Rn 217.003928(5) 0.54(5) ms 9/2+ 1,684.19 MeV
218Rn 218.0056013(25) 35(5) ms 0+ 1,692.26 MeV
219Rn 219.0094802(27) 3.96(1) s 5/2+ 1,700.33 MeV
220Rn 220.0113940(24) 55.6(1) s 0+ 1,699.09 MeV
221Rn 221.015537(6) 25.7(5) min 7/2(+) 1,707.16 MeV
222Rn 222.0175777(25) 3.8235(3) d 0+ 1,715.23 MeV
223Rn 223.02179(32)# 24.3(4) min 7/2 1,713.99 MeV
224Rn 224.02409(32)# 107(3) min 0+ 1,722.06 MeV
225Rn 225.02844(32)# 4.66(4) min 7/2- 1,730.13 MeV
226Rn 226.03089(43)# 7.4(1) min 0+ 1,728.89 MeV
227Rn 227.03541(45)# 20.8(7) s 5/2(+#) 1,736.96 MeV
228Rn 228.03799(44)# 65(2) s 0+ 1,745.03 MeV
Os valores marcados # não são puramente derivado a partir de dados experimentais, mas, pelo menos, parcialmente a partir de tendências sistemáticas. Gira com argumentos de atribuição fracos estão entre parênteses. 12

Abundância

Terra - A água do mar: 6E-16 mg/L 13
Terra -  crosta:  0.0000000000004 mg/kg = 4E-17% 13

Informação de Segurança


Material Safety Data Sheet - ACI Alloys, Inc.

Para maiores informações

Links externos:

Fontes

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:25.
(2) - Whitten, Kenneth W., Davis, Raymond E., and Peck, M. Larry. General Chemistry 6th ed.; Saunders College Publishing: Orlando, FL, 2000; p 944.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(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; p 4:133.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(11) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(12) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(13) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.