Radius Radon

Calculate the surface energy at 0 K of (100) planes of radon, given that its energy of vaporization is 35 x 10 erg/atom and that the crystal radius of the radon atom is 2.5 A. The crystal structure may be taken to be the same as for other rare gases. You may draw on the results of calculations for other rare gases. 

Element 86, the final member of the group, is a short-lived, radioactive element, formerly known as radium-emanation or niton or, depending on which radioactive series it originates in (i.e. which isotope) as radon, thoron, or actinon. It was first isolated and studied in 1902 by E. Rutherford and F. Soddy and is now universally known as radon (from radium and the termination-on adopted for the noble gases Latin radius, ray). 

We surveyed 20 homes for radon in 14 towns in New Jersey within a radius of 25 km from Chester, New Jersey in cooperation with Bell Communication Research, Inc. In a second geographical region encompassing 5 counties centered around Morris County, we measured radon concentrations in 50 residential buildings scattered in 24 towns through the cooperation of a local insurance company. 

When the radius of an aerosol particle, r, is of the order of the mean free path, i, of gas molecules, neither the diffusion nor the kinetic theory can be considered to be strictly valid. Arendt and Kallman (1926), Lassen and Rau (1960) and Fuchs (1964) have derived attachment theories for the transition region, r, which, for very small particles, reduce to the gas kinetic theory, and, for large particles, reduce to the classical diffusion theory. The underlying assumptions of the hybrid theories are summarized by Van Pelt (1971) as follows 1. the diffusion theory applies to the transport of unattached radon progeny across an imaginary sphere of radius r + i centred on the aerosol particle and 2. kinetic theory predicts the attachment of radon progeny to the particle based on a uniform concentration of radon atoms corresponding to the concentration at a radius of r + L... 

Fuchs model the radius and mass of the radon progeny are 4.9 x 10 8 cm and 5.46 x 10 22 g, respectively, for the above mentioned values of D, v and the other parameters. These calculated values are higher than would be expected for 218Po, suggesting that clustering occurs. 

While studying radium, Friedrich Ernst Dorn (1848—1916) found that it gave off a radioactive gas that, when studied in more detail, proved to be the sixth noble gas. Dorn was given credit for its discovery in 1900. He called it radon, a variation of the word radium. Sir Wdham Ramsay and R. W. Whytlaw-Gray, who also investigated the properties of radon, called it niton from the Latin word nitens, which means shining. Several other scientists who worked with radon named it thoron because of the transmutation of radon-220 from the decay of thorium. However, since 1923, the gas has been known as radon because it is the radioactive decay gas of the element radium. The name is derived from the Latin word radius, which means ray. ... 

Two samples of gas are separated in two rectangular 1.00-L chambers by a thin metal wall. One sample is pure helium and the other is pure radon. Both samples are at 27°C and show a pressure of 2.00 X 10 6 atm. Assuming that the metal wall separating the gases suddenly develops a circular hole of radius 1.00 X 10-6 m, calculate the pressure in each chamber after 10.0 h have passed. 

The name comes from the Latin radius, meaning ray. It was discovered by Marie and Pierre Curie in 1898 when they were studying uranium and other radioactive materials found in pitchblende. There is about 1 g of radium in 7 tons of pitchblende, but it is 3xl05 times more radioactive than uranium. It was isolated as a metallic element in 1911 by Marie Curie and Andre-Louis Debieme (1874-1949). Radium exists in small quantities associated with uranium ores. Radium is phosphorescent, so it has been used to make luminous paint, especially for watch dials, but, because it is highly radioactive, most uses are related to nuclear medicine or the energy industry. Radon gas is produced from radium and is a harmful by-product. 

F. Soddy and is now universally known as radon (from radium and the termination-on adopted for the noble gases Latin radius, ray). 

B. The atomic radius increases when going down a group so helium is the smallest and radon is the biggest. 

The KamLAND detector, shown in Figure 5, consists of a sphere of liquid scintillator, surrounded by neutron and gamma ray absorbing buffers made of liquid paraffin and water. The liquid scintillator is enclosed in a transparent nylon composite balloon that has low permeability to radon, a background-generating contaminant. The total mass of liquid scintillator is 1000 tons, filling a sphere with a radius of about 6.3 m. A 500 ton fiducial spherical volume is defined within the main volume to help reduce backgrounds from photomultiplier tubes and from external radioactive decay sources. The liquid parafrin buffer is enclosed in a spherical stainless steel vessel, which is in turn surrounded by a water Cerenkov veto counter. The entire detector is shielded by a rock overburden of 2700 meters of water equivalent (m.w.e.). 

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