Radon physical properties

Pure Elements. AH of the hehum-group elements are colorless, odorless, and tasteless gases at ambient temperature and atmospheric pressure. Chemically, they are nearly inert. A few stable chemical compounds are formed by radon, xenon, and krypton, but none has been reported for neon and belium (see Helium GROUP, compounds). The hehum-group elements are monoatomic and are considered to have perfect spherical symmetry. Because of the theoretical interest generated by this atomic simplicity, the physical properties of ah. the hehum-group elements except radon have been weU studied. 

Radon is the heaviest of the hehum-group elements and the heaviest of the normal gaseous elements. It is strongly radioactive. The most common isotope, Rn, has a half-life of 3.825 days (49). Radon s scarcity and radioactivity have severely limited the examination of its physical properties, and the values given ki Table 3 are much more uncertain than are the values Hsted for the other elements. 

Occurrence, extraction and uses Physical properties Compounds of xenon Compounds of krypton and radon... 

The primary route of exposure to radon and its progeny is inhalation. The degree of deposition and the subsequent absorption of inhaled radon and progeny is determined by physiological parameters, such as respiration rate and tidal volume and physical properties, such as the particle size distribution of the carrier aerosols and of the unattached fraction, the equilibrium state, and solubility coefficients (Crawford-Brown 1987 Holleman et al. 1969 Jacobi 1964). 

The group 8A elements, known as the noble gases, are all nonmetals that are gases at room temperature. They are all monatomic (that is, they consist of single atoms rather than molecules). Some physical properties of the noble-gas elements are listed in V TABLE 7.8. The high radioactivity of radon (Rn, atomic number 86) has limited the study of its reaction chemistry and some of its properties. 

Some physical properties of radon are listed in Table 1. Radon is moderately soluble in water and, therefore, can be absorbed by water flowing through rock and sand containing radon. Its solubility depends on water temperature the colder the water, the greater is radon s solubility. A measure of gas solubility in water is given by the solubility coefficient, which is defined as the ratio of the radon concentration in water to that in air. At 20°C, the solubility coefficient is 0.25, which means that radon is distributed preferentially in air rather than in water (in... 

In order to focus on more of the basic research problems related to radon, a symposium was organized in conjunction with the 191th National Meeting of the American Chemical Society. This volume presents most of the reports given at that symposium. There are five major groups of reports occurrence, measurement methods, physical and chemical properties of radon and its decay products, health effects, and mitigation of radon levels. 

You will find more information about the physical and chemical properties of radon in Chapter 3, about its uses in Chapter 4, and about your potential for exposure in Chapter 5. 

Important physical and chemical properties of radon are listed in Table 3-2. The radioactive properties of the important, short-lived daughters of radon-222 are listed in Table 3-3. The radon-222 decay series is depicted in Figure 3-1. 

Physical and Chemical Properties. Information is available on the physical and chemical properties of radon, and parameters that influence the behavior of radon in the environment have been determined. Therefore, no data needs are identified concerning physical and chemical properties of radon. 

A peer review panel was assembled for radon. The panel consisted of the following members Dr. Victor E. Archer, University of Utah Medical Center Dr. Douglas J. Crawford-Brown, University of North Carolina Dr. Richard Gerstle, private consultant and Dr. John Spengler, Harvard School of Public Health. These experts collectively have knowledge of radon s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in the Section 104(i)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

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