Radium elements

Beryllium is the lightest member of the alkaline earth metals family. These metals make up Group 2 (IIA) of the periodic table. They include beryllium, magnesium, calcium, strontium, barium, and radium. Elements in the same column of the periodic table have similar chemical properties. The periodic table is a chart that shows how the chemical elements are related to each other. 

Einsteinium is a member of the actinoid family. The actinoid elements are found in Row 7 of the periodic table, a chart that shows how chemical elements are related to each other. The actinoids fall between radium (element number 88) and rutherfordium (element number 104). They are usually listed in a separate row at the very bottom of the periodic table. 

Properties. — Radium is a white metal, with a melting point of about 700°. It blackens rapidly in the air due to the formation of the nitride. It chars paper, and reacts readily with water, forming the hydroxide. It dissolves easily in HC1. The element displays all the phenomena of radioactivity which are characteristic of its salts. On this account it is customary to speak of the amount of radium element present in a compound... 

Mesothorium is not a common article of commerce, so can scarcely be said to have established a market price. In 1913, it sold in England for 5 per milligram equivalent. In the United States it has sold as high as 875 per milligram equivalent, but the usual price runs from 40 to 60 per cent of that of radium for an equivalent gamma radiation. In 1921 the price ranged around 60 for an amount equivalent in activity to one gram of radium element. 

After a hard week s work Hahn and Strassmann succeeded in identifying no fewer than sixteen different activities. Their barium separations gave them their most startling results three previously unknown isotopes which they believed to be radium They reported their findings in November in Naturwissenschaften. The creation of radium, element 88, from uranium, they pointed out, must be due to the emission of two successive alpha particles. ... 

The white solid oxides MjO and M 0 are formed by direct union of the elements. The oxides MjO and the oxides M"0 of calcium down to radium have ionic lattices and are all highly basic they react exothermically with water to give the hydroxides, with acids to give salts, and with carbon dioxide to give carbonates. For example... 

The elements in Group II of the Periodic Table (alkaline earth metals) are. in alphabetical order, barium (Ba). beryllium (Be), calcium (Ca). magnesium (Mg), radium (Ra) and strontium (Sr). 

Poland, native country of Mme. Curie) Polonium, also called Radium F, was the first element discovered by Mme. Curie in 1898 while seeking the cause of radioactivity of pitchblend from Joachimsthal, Bohemia. The electroscope showed it separating with bismuth. 

Polonium is a very rare natural element. Uranium ores contain only about 100 micrograms of the element per ton. Its abundance is only about 0.2% of that of radium. 

From radium called niton at first, L. nitens, shining) 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. 

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 the 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 pCi/1. 

L. radius, ray) Radium was discovered in 1898 by Mme. Curie in the pitchblende or uraninite of North Bohemia, where it occurs. There is about 1 g of radium in 7 tons of pitchblende. The element was isolated in 1911 by Mme. Curie and Debierne by the electrolysis of a solution of pure radium chloride, employing a mercury cathode on distillation in an atmosphere of hydrogen this amalgam yielded the pure metal. 

Argon-40 [7440-37-1] is created by the decay of potassium-40. The various isotopes of radon, all having short half-Hves, are formed by the radioactive decay of radium, actinium, and thorium. Krypton and xenon are products of uranium and plutonium fission, and appreciable quantities of both are evolved during the reprocessing of spent fuel elements from nuclear reactors (qv) (see Radioactive tracers). 

Radon A radioactive element, the heaviest of the noble gases, formed by the radioactive decay of radium. 

The isolation and identification of 4 radioactive elements in minute amounts took place at the turn of the century, and in each case the insight provided by the periodic classification into the predicted chemical properties of these elements proved invaluable. Marie Curie identified polonium in 1898 and, later in the same year working with Pierre Curie, isolated radium. Actinium followed in 1899 (A. Debierne) and the heaviest noble gas, radon, in 1900 (F. E. Dorn). Details will be found in later chapters which also recount the discoveries made in the present century of protactinium (O. Hahn and Lise Meitner, 1917), hafnium (D. Coster and G. von Hevesey, 1923), rhenium (W. Noddack, Ida Tacke and O. Berg, 1925), technetium (C. Perrier and E. Segre, 1937), francium (Marguerite Percy, 1939) and promethium (J. A. Marinsky, L. E. Glendenin and C. D. Coryell, 1945). 

Radium, the last element in the group, was isolated in trace amounts as the chloride by P. and M. Curie in 1898 after their historic processing of tonnes of pitchblende. It was named by Mme Curie in allusion to its radioactivity, a word also coined by her (Latin radius, a ray) the element itself was isolated electrolytically via an amalgam by M. Curie and A. Debieme in 1910 and its compounds give a carmine-red flame test. 

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). 

Marie Curie (Paris) discovery of the elements radium and polonium, the isolation of radium, and the study of the nature and compounds of this remarkable element. 

Although the Curies noted that one equivalent gram of radium released one hundred calorics of heat per hour, they were uninterested in the practical implications of this, as they were both devoted to pure scientific discovery. During their work with pitchblende in 1898, the Curies discovered two new radioactive elements, which they named polonium (in honor of Marie s homeland) and radium. By 1902 they had isolated a pure radium salt and made the first atomic weight determination. 

Although the nucleus of the uranium atom is relatively stable, it is radioactive, and will remain that way for many years. The half-life of U-238 is over 4.5 billion years the half-life of U-235 is over 700 million years. (Half-life refers to the amount of time it takes for one half of the radioactive material to undergo radioactive decay, turning into a more stable atom.) Because of uranium radiation, and to a lesser extent other radioactive elements such as radium and radon, uranium mineral deposits emit a finite quantity of radiation that require precautions to protect workers at the mining site. Gamma radiation is the... 

In 1898, Marie and Pierre Curie isolated two new radioactive elements, which they named radium and polonium. To obtain a few milligrams of these elements, they started with several tons of pitchblende ore and carried out a long series of tedious separations. Their work was done in a poorly equipped, unheated shed where the temperature reached 6°C (43°F) in winter. Four years later, in 1902, Marie determined the atomic mass of radium to within 0.5%, working with a tiny sample. 

The curie was supposed to be the activity of a one-gram sample of radium, the element discovered by the Curies it isn t quite.)... 

Only five of the seventh-row elements are found in nature radium, actinium, thorium, protac-... 

Modern periodic tables sometimes differ in which elements are placed immediately to the right of barium and radium. In some cases, the elements are lanthanum and... 

FIGURE 14.19 The elements of Croup 2 (a) beryllium (b) magnesium (c) calcium id) strontium and (c) barium. The four central elements of the group (magnesium through barium) were discovered bv I lumphry Davy in a single year (1 808). The two outer elements were discovered later beryllium in 1828 (by Friedrich Wohler) and radium (which is not shown here) in 1898 (by Pierre and Marie Curie). 

The natural occurrence of the group-IIA elements ranges from common to rare e.g., Ca is 5th in the order of atomic abundance of the elements in the earth s crust. Mg is 7th, Ba and Sr are 21st and 22nd, respectively, and Be is 32nd . Radium is of extremely limited availability. It does occur naturally, although it has neither stable nor long-lived radioaetive isotopes it is found in association with U, since ll/2... 

When Z gets big enough, no number of neutrons is enough to stabilize the nucleus. Notice in Figure 2-20 that there are no stable nuclei above bismuth, Z — 83. Some elements with higher Z are found on Earth, notably radium (Z = 88), thorium (Z = 90), and uranium (Z = 92), but all such elements are unstable and eventually disintegrate into nuclei with Z < 83. Consequently, the set of stable nuclei, those that make up the world of normal chemistry and provide the material for all terrestrial chemical reactions, is a small subset of all possible nuclei. 

Between barium (Group 2, element 56) and lutetium (Group 3, element 71), the 4f orbitals fill with electrons, giving rise to the lanthanides, a set of 14 metals named for lanthanum, the first member of the series. The lanthanides are also called the rare earths, although except for promethium they are not particularly rare. Between radium (Group 2, element 88) and lawrenclum (Group 3, element 103), are the 14 actinides, named for the first member of the set, actinium. The lanthanides and actinides are also known as the inner transition metals. 

In contrast to thermal ionization methods, where the tracer added must be of the same element as the analyte, tracers of different elemental composition but similar ionization efficiency can be utilized for inductively coupled plasma mass spectrometry (ICPMS) analysis. Hence, for ICPMS work, uranium can be added to thorium or radium samples as a way of correcting for instrumental mass bias (e g., Luo et al. 1997 Stirling et al. 2001 Pietruszka et al. 2002). The only drawback of this approach is that small inter-element (e g., U vs. Th) biases may be present during ionization or detection that need to be considered and evaluated (e.g., Pietruszka et al. 2002). 

Figure 1. Schematic diagram showing a TRU-spec extraction chromatography method for separation of uranium, thorium, protactinium, and radium from a single rock aliquot. Further purification for each element is normally necessary for mass spectrometric analysis. Analysis of a single aliquot reduces sample size requirements and facilitates evaluation of uranium-series dating concordance for volcanic rocks and carbonates. For TIMS work where ionization is negatively influenced by the presence of residual extractant, inert beads are used to help remove dissolved extractant from the eluant.

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