transition elements


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transition elements

or

transition metals,

in chemistry, group of elements characterized by the filling of an inner d electron orbital as atomic number increases. This includes the elements from titanium to copper, and those lying in the columns below them in the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
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. Many of the chemical and physical properties of the transition elements are due to their unfilled d orbitals. In the elements of the lanthanide serieslanthanide series,
a series of metallic elements, included in the rare-earth metals, in Group 3 of the periodic table. Members of the series are often called lanthanides, although lanthanum (atomic number 57) is not always considered a member of the series.
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 and the actinide seriesactinide series,
a series of radioactive metallic elements in Group 3 of the periodic table. Members of the series are often called actinides, although actinium (at. no. 89) is not always considered a member of the series.
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 the inner f orbital is filled as atomic number increases; those elements are often called the inner transition elements. Transition elements generally exhibit high density, high melting point, magnetic properties, variable valence, and the formation of stable coordination complexes. Their variable valence is due to the electrons in the d orbitals. The study of the complex ionscomplex ion,
charged molecular aggregate (see ion), consisting of a metallic atom or ion to which is attached one or more electron-donating molecules. In some complex ions, such as sulfate, SO4−2
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 and compounds formed by transition metals is an important branch of chemistry. Many of these complexes are highly colored and exhibit paramagnetism.

Transition Elements

 

(also called transition metals), the 61 chemical elements that fall into subgroups IB through VIIIB in D. I. Mendeleev’s periodic system of the elements. With respect to atomic structure, transition elements are characterized by unfilled inner electron shells. Transition elements are divided into d-elements and f-elements: in the d-elements electrons are added to the 2d-, 4d-, 5d-, and 6d-subshells, and in the f-elements electrons are added to the 4f-subshell in the lanthanides and the 5f-subshell in the actinides. These electron configurations account for certain specific properties of transition elements, including the ability to form complexes and to exhibit ferromagnetism. (See.)

References in periodicals archive ?
Such behavior is similar to the result obtained in [8, 9] for Ni and seems to be a generic feature for alloying with transition elements in dilute limit in general [39].
The magnetochemistry of transition elements provides grants to state whether the d electrons are paired or not.
It may be noted that in the mesh the gray-shaded region depicts three-dimensional elements encircling the crack only and the rest is comprised of two-dimensional elements covering patched and the unpatched regions with transition elements located in-between.
These two different regions can then be coupled by utilization of transition elements. The transition elements need to be compatible, in order to avoid hanging nodes.
Mn is preferred for the doping of ZnO due to the fact that the d electron of Mn at [t.sub.2g] level can easily overlap with the ZnO's valence bond as compared with other transition elements. There are various studies which showed, that Mn-doped semiconductors have influenced the physical, chemical, and structural properties of undoped ZnO nanoparticles.
"We have prepared a strategic plan for the heritage group that is divided into three elements, which are heritage elements, complementary elements and transition elements. The first element includes the souq saleh (the traditional market), the old city, Ajman fort (museum), Ajman creek and Eid prayer space." He added that there are plans of preserving crafts and shopping activities in the traditional market by transforming the market from the pathway to a roofed market.
Chemists from Canada, the US, Scotland, and France introduce graduate students and researchers to metal oxides, particularly those with one or more transition elements, which have long served as the foundation of solid-state inorganic chemistry.
Wald sums up, "There are atoms that form the bulk of organic molecules: C, H, N, and O, and in special instances S and P; there are major mono-atomic ions [Na.sup.+], [K.sup.+], [Mg.sup.++], [Ca.sup.++], and [Cl.sup.-]; there are trace elements, mostly transition elements, and hence adapted to fill the roles in which we mainly find them, as nuclei and ligands in metallo-organic complexes and oxido-reduction enzymes containing Fe, Mn, Co, Cu, and Zn." He proceeds to a detailed discussion of the roles of C, H, N, O, P, and S, and argues why these cannot be fulfilled by other elements for life in an aqueous environment.
* Increased insight by consciously attending to transition elements within one's own practice, whatever particular therapeutic, advisory or coaching model is used.
Between individual aerial pieces, choreographed dance and other circus routines on the ground will act as transition elements.
For transition elements, where both single-phase and two-phase refrigerant are present, this assumption introduces some error in the capacity calculation and, more importantly, results in dual-valued property functions that may trap the numerical solver at an unconverged point in the solution domain.
There have been some calculations for K shells for inert gases and selected transition elements.

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