Lawrencium atomic properties

A further group of elements, the transuranium elements, has been synthesized by artificial nuclear reactions in the period from 1940 onwards their relation to the periodic table is discussed fully in Chapter 31 and need not be repeated here. Perhaps even more striking today are the predictions, as yet unverified, for the properties of the currently non-existent superheavy elements.Elements up to lawrencium (Z = 103) are actinides (5f) and the 6d transition series starts with element 104. So far only elements 104-112 have been synthesized, ) and, because there is as yet no agreement on trivial names for some of these elements (see pp. 1280-1), they are here referred to by their atomic numbers. A systematic naming scheme was approved by lUPAC in 1977 but is not widely used by researchers in the field. It involves the use of three-letter symbols derived directly from the atomic number by using the... 

The transeinsteinium actinides, fermium (Fm), mendelevium (Md), nobelium (No), and lawrencium (Lr), are not available in weighable (> ng) quantities, so these elements are unknown in the condensed bulk phase and only a few studies of their physicochemical behavior have been reported. Neutral atoms of Fm have been studied by atomic beam magnetic resonance 47). Thermochromatography on titanium and molybdenum columns has been employed to characterize some metallic state properties of Fm and Md 61). This article will not deal with the preparation of these transeinsteinium metals. 

The use of the continuation of the periodic table, the predicted electronic configurations, and the trends which become obvious from the calculations plus the semiempirical and empirical methods, allows us to offer some detailed predictions of the properties of the elements beyond lawrencium (Z = 103) (S5). Of course, these elements will first be produced at best on a one atom at a time basis, and they offer little hope of ultimate production in the macroscopic quantities that would be required to verify some of these predictions. However, many of the predicted specific macroscopic properties, as well as the more general properties predicted for the other elements, can stiU be useful in designing tracer experiments for the chemical identification of any of these elements that might be synthesized. 

The second series of inner transition elements, the actinides, have atomic numbers ranging from 90 (thorium, Th) to 103 (lawrencium, Lr). All of the actinides are radioactive, and none beyond uranium (92) occur in nature. Like the transition elements, the chemistry of the lanthanides and actinides is unpredictable because of their complex atomic structures. What could be happening at the subatomic level to explain the properties of the inner transition elements In Chapter 7, you ll study an expanded theory of the atom to answer this question. 

The modern periodic table, in which the elements are arranged according to the atomic numbers in columns (groups) and rows (periods) and presented so as to emphasize their periodic properties, from hydrogen 1 to lawrencium 103, is... 

The two rows at the bottom of the periodic table that have been separated from the rest of the table are called lanthanides and actinides. The lanthanides, the elements in the first row, from cerium (Ce) to lutetium (Lu), are called the lanthanides because their properties are similar to those of lanthanum (La). Historically, they have also been called the rare earths because they were believed to be much rarer than other metals. The elements in the second row, from thorium (Th) to lawrencium (Lr), are called the actinides because they are similar to actinium (Ac). Notice that the atomic numbers of the lanthanides all fit between numbers 57 (La) and 72 (Hf). The atomic numbers of the actinides all fit between numbers 89 (Ac) and 104 (Rf). 

The actinoid series encompasses the fourteen chemical elements with atomic numbers from 90 to 103, thorium (Th) to lawrencium (Lr). The actinoid series derives its name from the group-IIla element actinium (Ac) which can be included in the series for the purpose of comparison. Only Th and uranium (U) occur in usable quantities in nature. The other actinoids are man-made elements. Pure Th is a silvery-white metal which is air-stable and retains its luster for several months. U exhibits three crystallographic modifications as follows a (688°C) —> P (776°C) —> U is a heavy, silvery-white metal. The luster of freshly prepared americium (Am) is white and more silvery than neptunium (Np) or plutonium (Pu) prepared in the same manner. All actinoid elements are radioactive. Table 2.113 sutnmarizes some physical properties of actinoid metals (Th, U and Am). 

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