synthetic elements definition of synthetic elements in the Free Online Encyclopedia.

synthetic elements, in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium technetium (tĕknē`shēəm) [Gr.
..... Click the link for more information. (at. no. 43), which was the first element to be synthesized, promethium promethium (prōmē`thēəm), artificially produced radioactive chemical element; symbol Pm; at. no. 61; mass no.
..... Click the link for more information. (at. no. 61), astatine astatine (ăs`tətēn,–tĭn) [Gr.,=unstable], semimetallic radioactive chemical element; symbol At; at. no. 85; at. wt.
..... Click the link for more information. (at. no. 85), francium francium (frăn`sēəm) [from France], radioactive chemical element; symbol Fr; at. no. 87; mass no.
..... Click the link for more information. (at. no. 87), and the transuranium elements transuranium elements, in chemistry, radioactive elements with atomic numbers greater than that of uranium (at. no. 92). All the transuranium elements of the actinide series were discovered as synthetic radioactive isotopes at the Univ.
..... Click the link for more information. (at. no. 93 and beyond in the periodic table periodic 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
..... Click the link for more information. ). Some of these elements have since been shown to exist in minute amounts in nature, usually as short-lived members of natural radioactive decay series (see radioactivity radioactivity, spontaneous disintegration or decay of the nucleus of an atom by emission of particles, usually accompanied by electromagnetic radiation . The energy produced by radioactivity has important military and industrial applications.
..... Click the link for more information. ).

The synthetic elements through at. no. 100 (fermium fermium (fûr`mēəm) [for Enrico Fermi ], artificially produced radioactive chemical element; symbol Fm; at. no. 100; mass no.
..... Click the link for more information. ) are created by bombarding a heavy element, such as uranium or plutonium, with neutrons or alpha particles. The synthesis of the transfermium elements (elements with at. no. 101 or greater) is accomplished by the fusion of the nuclei of two lighter elements. Elements 101 through 106 were first produced by fusing the nuclei of slightly lighter elements, such as californium californium (kăl`ĭfôr'nēəm)
..... Click the link for more information. , with those of light elements, such as carbon carbon [Lat.,=charcoal], nonmetallic chemical element; symbol C; at. no. 6; at. wt. 12.011; m.p. about 3,550°C;; graphite sublimes about 3,375°C;; b.p. 4,827°C;; sp. gr. 1.8–2.1 (amorphous), 1.9–2.3 (graphite), 3.15–3.
..... Click the link for more information. . Elements 107 through 112 were first produced by fusing the nuclei of medium-weight elements, such as bismuth bismuth (bĭz`məth) [Ger. Weisse Masse=white mass], metallic chemical element; symbol Bi; at. no. 83; at. wt. 208.9804; m.p.
..... Click the link for more information. or lead lead, metallic chemical element; symbol Pb [Lat. plumbum]; at. no. 82; at. wt. 207.2; m.p. 327.502°C;; b.p. about 1,740°C;; sp. gr. 11.35 at 20°C;; valence +2 or +4.
..... Click the link for more information. , with those of other medium-weight elements, such as iron iron, metallic chemical element; symbol Fe [Lat. ferrum]; at. no. 26; at. wt. 55.847; m.p. about 1,535°C;; b.p. about 2,750°C;; sp. gr. 7.87 at 20°C;; valence +2, +3, +4, or +6. Iron is biologically significant.
..... Click the link for more information. , nickel nickel, metallic chemical element; symbol Ni; at. no. 28; at. wt. 58.69; m.p. about 1,453°C;; b.p. about 2,732°C;; sp. gr. 8.902 at 25°C;; valence 0, +1, +2, +3, or +4.
..... Click the link for more information. , or zinc zinc, metallic chemical element; symbol Zn; at. no. 30; at. wt. 65.38; m.p. 419.58°C;; b.p. 907°C;; sp. gr. 7.133 at 25°C;; valence +2. Zinc is a lustrous bluish-white metal. It is found in Group 12 of the periodic table .
..... Click the link for more information. . Element 114 was first produced by fusing the nuclei of plutonium plutonium (pl
..... Click the link for more information. and calcium calcium (kăl`sēəm) [Lat.,=lime], metallic chemical element; symbol Ca; at. no. 20; at. wt. 40.08; m.p. about 839°C;; b.p.
..... Click the link for more information. and subsequently by fusing the nuclei of lead and krypton krypton (krĭp`tŏn) [Gr.,=hidden], gaseous chemical element; symbol Kr; at. no. 36; at. wt. 83.80; m.p. −156.6°C;; b.p.
..... Click the link for more information. , as was element 116. Element 115 was produced by bombarding americium americium (ămərĭ`shēəm), artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no.
..... Click the link for more information. with calcium, and element 113 resulted from the radioactive decay of element 115. The claim by Lawrence Berkeley National Laboratory to have created element 118 has been retracted.)

The transfermium elements are produced in very small quantities (one atom at a time), and identification is therefore very difficult because of half-lives half-life, measure of the average lifetime of a radioactive substance (see radioactivity ) or an unstable subatomic particle. One half-life is the time required for one half of any given quantity of the substance to decay.
..... Click the link for more information. ranging from minutes to milliseconds and the need to identify the products by methods other than known chemical separations. This has led to controversy over reported discoveries and over the naming of the elements. It has been predicted that one isotope of element 114—containing 114 protons and 184 neutrons—would be very stable because its nucleus would have a full complement of protons and neutrons. Termed an "island of stability," its half-life might be measured in years. However, none of the three isotopes of element 114 synthesized as yet have as many as 184 neutrons, and their half-lives are still in the millisecond range.