Radium atom

The number of radium atoms that break up per second per gram is 3.7(10 ). 

It is found that the number Q. of radium atoms which break up per gram of... 

Actinium-227 occurs in uranium ore and is a decay product of uranium-235. It is found in equilibrium with its decay products. It is prepared hy homhard-ing radium atoms with neutrons. Chemically, the metal is produced hy reducing actinium fluoride with lithium vapor at 1,100°C to 1,300°C. 

It is found that the number Q of radium atoms which break up per gram of radium in one second is, roughly, Q = 3.7(1010). Find the time for 1/2 the... 

It is assumed that radium that has been deposited in the lung as a radium salt enters the systemic circulation either as that salt or as individual radium atoms at a rate dependent upon the solubility and chemical characteristics of the specific radium salt involved. Subsequently, these salts or radium atoms would be systemically transported in the same manner as radium acquired by oral or parenteral administration. However, some of the radium in the lung could be retained for a long time before this process is completed. The ultimate distribution, many years after an inhalation exposure, would probably be very similar to that of other routes of administration that is, most of the radium that was retained in the body would eventually be deposited in the skeleton (Marinelli et al. 1953). 

The unit curie used in the last problem is named after Pierre and Marie Curie, who did pioneering experiments with radium in the nineteenth century. One curie (3.7 x 1010 disintegrations per second) is the decay rate of one gram of radium, atomic mass 226 g mol-1. What is the half-life of radium-226 ... 

RANDON A naturally occurring radioactive inert gas formed by radioactive decay of radium atoms in soil and rocks and that cannot be seen, smelled, or tasted. 

Consider, for example, the decomposition of radium into helium and radon. It is found that about one radium atom in two thousand decomposes in a year. Suppose we are asked to predict the state of a particular radium atom at some future time, say after ten years. All we can say is that it will either be unchanged or will have decomposed, and that the chance of... 

This paint glowed in the dark, because it contained radium (atomic number 88), which is... 

The American Physics Teacher The Radium Atom (p. 181) Volume 7, Number 3, June 1939... 

Radon A naturally occurring radioactive inert gas that cannot be seen, smelled, or tasted, formed by radioactive decay of radium atoms in soil and rocks RDA Recommended daily allowance the National Academy of Sciences sets the required nutrient values for healthy people in the United States. The values take into consideration the needs of all individuals RDI Recommended daily intake... 

The amount of radon present in a steady state with one gram of radium can be calculated by consideration of the first-order reaction-rate equations discussed in Chapter 19. The reaction-rate constant for the decomposition of radium is inversely proportional to its half-life. Hence when a steady state exists, and the number of radium atoms undergoing decomposition is equal to the number of radon atoms undergoing decomposition, the ratio of the numbers of radon atoms and radium atoms present must be equal to the ratio of their half-lives. 

Actinium is found in uranium ores. An ore is a mineral mined for the elements it contains. Actinium is produced by the radioactive decay, or breakdown, of uranium and other unstable elements. Actinium can also be artificially produced. When radium is bombarded with neutrons, some of the neutrons become part of the nucleus. This increases the atomic weight and the instability of the radium atom. The unstable radium decays, gives off radiation, and changes to actinium. Actinium metal of 98 percent purity—used for research purposes—can be made by this process. 

Sheppard, M.I., 1980. The environmental behaviour of radium. Atomic Energy of Canada Ltd., Report PAECL-6796,28 pp. 

While the radium atoms are intact they obey the same laws as other atoms, such as the laws of definite and multiple proportion. 

The disintegration of the radium atom is independent of the chemical combination in which it is placed, and proceeds at the same rate whether the atom is in the metallic state or in combination as a halide, carbonate, sulfate, etc. 

When Fermi s group analyzed the products of the neutron bombardment, it appeared to them that radium had been produced, especially since they had no reason to even suspect that barium could be a product. Since radium is the daughter element formed by two successive alpha decays of a uranium atom, they decided their quest for a transuranium element was unsuccessful. Subsequently, Otto Hahn (1879-1968), Fritz Strassmann (1902-80), and Lise Meitner (1878-1968), all from Germany, reinterpreted the results to show that it was not radium atoms that had been formed, but barium atoms instead from the nuclear fission of uranium. Thus, Fermi and his group just missed discovering fission. 

How many atoms of radium are decaying each second (b) How long will it take before half of the radium atoms have disintegrated ... 

When the radium atom lies close to the surface of the grain of the solid, the recoil energy (85 keV per atom) that the radon atoms gains during decay of the parent may be sufficient to eject the gas atom from the grain. Alternatively, the radon atom may escape by diffusion before it undergoes the decay. 

Radium oripnates as an intermediate product in the radioactive decay of uranium-238 to the stable nuclide lead-206. The radium atom has 88 protons and 88 electrons its atomic number is iherfbre 88. 

Practice Problem A Without referring to Figure 6.25, write the electron configuration for a radium atom (Z = 88) in the ground state. 

The heaviest known alkaline earth metal is radium, atomic number 88. Find the atomic numbers of the as yet undiscovered next two members of the series. 

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