Polonium half-life

Polonium-210 is a low-melting, fairly volatile metal, 50% of which is vaporized in air in 45 hours at 55C. It is an alpha emitter with a half-life of 138.39 days. A milligram emits as many alpha particles as 5 g of radium. 

Twenty five isotopes of polonium are known, with atomic masses ranging from 194 to 218. Polonium-210 is the most readily available. Isotopes of mass 209 (half-life 103 years) and mass 208 (half-life 2.9 years) can be prepared by alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron, but these are expensive to produce. 

Gr. aktis, aktinos, beam or ray). Discovered by Andre Debierne in 1899 and independently by F. Giesel in 1902. Occurs naturally in association with uranium minerals. Actinium-227, a decay product of uranium-235, is a beta emitter with a 21.6-year half-life. Its principal decay products are thorium-227 (18.5-day half-life), radium-223 (11.4-day half-life), and a number of short-lived products including radon, bismuth, polonium, and lead isotopes. In equilibrium with its decay products, it is a powerful source of alpha rays. Actinium metal has been prepared by the reduction of actinium fluoride with lithium vapor at about 1100 to 1300-degrees G. The chemical behavior of actinium is similar to that of the rare earths, particularly lanthanum. Purified actinium comes into equilibrium with its decay products at the end of 185 days, and then decays according to its 21.6-year half-life. It is about 150 times as active as radium, making it of value in the production of neutrons. 

Radon-222 [14859-67-7] Rn, is a naturally occuriing, iaert, radioactive gas formed from the decay of radium-226 [13982-63-3] Ra. Because Ra is a ubiquitous, water-soluble component of the earth s cmst, its daughter product, Rn, is found everywhere. A major health concern is radon s radioactive decay products. Radon has a half-life of 4 days, decayiag to polonium-218 [15422-74-9] Po, with the emission of an a particle. It is Po, an a-emitter having a half-life of 3 min, and polonium-214 [15735-67-8] Po, an a-emitter having a half-life of 1.6 x lO " s, that are of most concern. Polonium-218 decays to lead-214 [15067-28A] a p-emitter haviag = 27 min, which decays to bismuth-214 [14733-03-0], a p-emitter haviag... 

Polonium, because of its very low abundance and very short half-life, is not obtained from natural sources. Virtually all our knowledge of the physical and chemical properties of the element come from studies on Po which is best made by neutron irradiation of in a nuclear reactor ... 

The final member of the group, actinium, was identified in uranium minerals by A. Debieme in 1899, the year after P. and M. Curie had discovered polonium and radium in the same minerals. However, the naturally occurring isotope, Ac, is a emitter with a half-life of 21.77 y and the intense y activity of its decay products makes it difficult to study. 

Polonium-210 decays to Pb-206 by alpha emission. Its half-life is 138 days. What volume of helium at 25°C and 1.20 atm would be obtained from a 25.00-g sample of Po-210 left to decay for 75 hours ... 

C22-0088. Polonium-210 has a half-life of 138.4 days. If a sample contains 5.0 mg of Po, how many milligrams will remain after 365 days How many emissions per second will this residue emit ... 

Polonium - the atomic number is 84 and the chemical symbol is Po. This radioactive metal was also known as radium-F. The name derives from Poland , the native country of Marie Sklodowska Curie. It was discovered by Pierre and Marie Curie in 1898, from its radioactivity. It was independently found by the German chemist Willy Marckwald in 1902 and called radiotellurium. The longest half-life associated with this unstable element is 102 year ° Po. 

ISOTOPES All 41 isotopes of astatine are radioactive, with half-lives ranging from 125 nanoseconds to 8.1 hours. The isotope As-210, the most stable isotope with an 8.1-hour half-life, is used to determine the atomic weight of astatine. As-210 decays by alpha decay into bismuth-206 or by electron capture into polonium-210. 

Radon-222 also undergoes radioactive decay and has a radioactive half-life of 3.8 days. Radon-220 and -219 have half-lives measured in seconds and are not nearly as abundant as Radon-222. Thus the discussion of radon health effects here centers on Radon-222. Radon-222 decays into radon daughters or progeny, which are radioactive elements. Two of these (polonium-218 and polonium-214) emit alpha particles (high-energy, high-mass particles, each consisting of two protons and... 

Radon is another example of a very curious and toxic compound that many of us regularly inhale, hopefully in small amounts. For those regularly exposed to radon, there is an increased risk for lung cancer and, for those that smoke, radon exposure results in a three-fold increase in the incidence of lung cancer. In the United States it is estimated that indoor radon exposure causes between 7000 and 30,000 lung cancer-related deaths each year, second only to tobacco smoking. Radon-222 is a colorless and odorless radioactive gas that results from the decay of radium-226, which is widely distributed in the earth s crust. Radon decays with a half-life of 3.8 days into solid particles of polonium. It is actually the breakdown of... 

Unlike its lower homologues, sulfur, selenium, and tellurium, polonium has no long-lived or stable isotopes. It has, in fact, one of the most unstable nuclei of naturally occurring elements, the only readily accessible isotope being that of mass 210 this decays by alpha emission with a half-life of 138.4 days and occurs in nature as the penultimate member of the radium decay series, the last three stages being... 

Uranium-238 has a half-life of 4.5 billion years, and polonium-214 has a half-life of 0.00016 second. So, which would you rather hold in your hands 1 gram of uranium-238 or 1 gram ofpolonium-214 ... 

ACTINON. The name of the isotope of radon (emanation), which occurs in the naturally occurring actinium, series being, produced by alpha-decay of actinium X, which is itself a radium isotope. Achnon has an atomic number of 86, a mass number of 219, and a half-life of 3.92 seconds, emitting an alpha particle to form polonium-215 (Actinium A). See also Chemical Elements and Radioactivity. 

Radium is chemically similar to barium it displays a characteristic optical spectrum its salts exhibit phosphorescence in the dark, a continual evolution of heat taking place sufficient in amount to raise the temperature of 100 times its own weight of water 1°C every hour and many remarkable physical and physiological changes have been produced. Radium shows radioactivity a million times greater than an equal weight of uranium and. unlike polonium, suffers no measurable loss of radioactivity over a short period of time (its half life is 1620 years). From solutions of radium salts, there is separable a radioactive gas radium emanation, radon, which is a chemically ineit gas similai to xenon and disintegrates with a half life of 3.82 days, with the simultaneous formation of another radioactive element, Radium A (polonium-218). 

Polonium-209, an a emitter, has a half-life of 102 years. How many a particles are emitted in 1.0 s from a 1.0 ng sample of 209Po ... 

The total number of publications that describes organometallic chemistry of polonium makes up one of the smallest segments of chemical literatme. The element is very rare its natural concentration in pitchblende ores is only about 0.1 mg per ton. Twenty-one isotopes are known, all of which are radioactive. Of these, °Po is most commonly used for chemical purposes because it can be synthesized in milhgram amounts from g Bi by an (n,y) reaction. The gg Bi undergoes /3-decay (5.0 days) to produce g4°Po. This isotope has a half-life of about 138 days. Although the isotopes 209pQ... 

Polonium is found in the natural environment, especially in uranium and thorium ores. Of seven natural radionuclides of polonium, Po is the most important. It is an alpha emitter with energy of 5.305 MeV and half-life of 138.376 days [24]. Polonium is a very radiotoxic element and undergoes strong bioaccumulation in land and aquatic organisms [1]. 

The half-life of polonium-218 is 3.0 min. If you start with 16 mg of polonium-218, how much time must pass for only 1.0 mg to remain ... 

The half-life of polonium-210 is 138.4 days. How many milligrams of polo-... 

Using the half-life given in Table 25-5, how much of a 1.0-g polonium-214 sample remains after 818 microseconds ... 

Polonium is a radioactive, low-melting metalloid. It was identified in uranium ores in 1898 by the Curies. Its most stable isotope, " Po, has a half-life of 103 y. 

Radon-222 decays to polonium-218 by alpha emission with a half-life of... 

The first example [33] was thorium emanation, Rn (diffusing from thorium compounds now known to contain Ra in approximate equilibrium with the ancestor radiothorium , Th), having exponential decay of its radioactivity with a half-life tjyj close to one minute. The weak point about the three emanations and their radioactive deposit (such as the polonium isotopes radium A , Po, and thorium A , Po) was the fact that their character as elements, rather than some kind of mobile ephemeral contamination, was only firmly established a few years later. 

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