actinide series
actinide series
ac′ti•nide se`ries
(ˈæk təˌnaɪd)n.
Noun | 1. | ![]() |
单词 | actinide series | |||
释义 | actinide seriesactinide seriesac′ti•nide se`ries(ˈæk təˌnaɪd)n.
actinide seriesactinide series,a series of radioactive metallic elements in Group 3 of 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 ..... Click the link for more information. . Members of the series are often called actinides, although actiniumactinium [Gr.,=like a ray], radioactive chemical element; symbol Ac; at. no. 89; mass number of most stable isotope 227; m.p. about 1,050°C;; b.p. 3,200°C;±300°C;; sp. gr. 10.07; valence +3. Actinium is a silver-white metal with a cubic crystalline structure. ..... Click the link for more information. (at. no. 89) is not always considered a member of the series. The series always includes the 14 elements with atomic numbers 90 through 103. The other members are (in order of increasing atomic number) thoriumthorium [from Thor], radioactive chemical element; symbol Th; at. no. 90; mass number of most stable isotope 232; m.p. about 1,750°C;; b.p. about 4,790°C;; sp. gr. 11.7 at 20°C;; valence +4. Thorium is a soft, ductile, lustrous, silver-white, radioactive metal. ..... Click the link for more information. , protactiniumprotactinium , radioactive chemical element; symbol Pa; at. no. 91; mass number of most stable isotope 231; m.p. greater than 1,600°C;; b.p. 4,026°C;; sp. gr. 15.37 (calculated); valence +4, +5. Protactinium is a malleable, shiny silver-gray radioactive metal. ..... Click the link for more information. , uraniumuranium , radioactive metallic chemical element; symbol U; at. no. 92; mass number of most stable isotope 238; m.p. 1,132°C;; b.p. 3,818°C;; sp. gr. 19.1 at 25°C;; valence +3, +4, +5, or +6. ..... Click the link for more information. , neptuniumneptunium , radioactive chemical element; symbol Np; at. no. 93; mass number of most stable isotope 237; m.p. about 640°C;; b.p. 3,902°C; (estimated); sp. gr. 20.25 at 20°C;; valence +3, +4, +5, or +6. Neptunium is a ductile, silvery radioactive metal. ..... Click the link for more information. , plutoniumplutonium , radioactive chemical element; symbol Pu; at. no. 94; mass no. of most stable isotope 244; m.p. 641°C;; b.p. 3,232°C;; sp. gr. 19.84 at 20°C;; valence +3, +4, +5, or +6. ..... Click the link for more information. , americiumamericium , artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175°C;; b.p. about 2,600°C;; sp. gr. 13.67 at 20°C;; valence +2, +3, +4, +5, or +6. ..... Click the link for more information. , curiumcurium , artificially produced radioactive chemical element; symbol Cm; at. no. 96; mass no. of most stable isotope 247; m.p. about 1,340°C;; b.p. 3,110°C;; sp. gr. 13.5 (calculated); valence +3, +4. ..... Click the link for more information. , berkeliumberkelium [from Berkeley], artificially produced radioactive chemical element; symbol Bk; at. no. 97; mass no. of most stable isotope 247; m.p. about 1,050°C;; b.p. about 2,590°C;; sp. gr. 14 (estimated); valence +3, +4. ..... Click the link for more information. , californiumcalifornium [from California], artificially produced, radioactive metallic chemical element; symbol Cf; at. no. 98; mass no. of most stable isotope 251; m.p. about 900°C;; b.p. about 1,470°C;; density unknown; valence +3. ..... Click the link for more information. , einsteiniumeinsteinium [for Albert Einstein], artificially produced radioactive chemical element; symbol Es; at. no. 99; mass no. of most stable isotope 252; m.p. about 860°C;; b.p. and sp. gr. unknown; valence +2, +3. ..... Click the link for more information. , fermiumfermium [for Enrico Fermi], artificially produced radioactive chemical element; symbol Fm; at. no. 100; mass no. of most stable isotope 257; m.p. 1,527°C;; b.p. and sp. gr. unknown; valence +2, +3. Fermium is a member of Group 3 of the periodic table. ..... Click the link for more information. , mendeleviummendelevium , artificially produced radioactive chemical element; symbol Md; at. no. 101; mass no. of most stable isotope 258; m.p. 827°C;; b.p. and sp. gr. unknown; valence +1, +2, +3. Mendelevium is a metal of the actinide series in Group 3 of the periodic table. ..... Click the link for more information. , nobeliumnobelium , artificially produced radioactive chemical element; symbol No; at. no. 102; mass no. of most stable isotope 259; m.p. 827°C;; b.p. and density unknown; valence +2, +3. It is a metal of the actinide series in Group 3 of the periodic table. ..... Click the link for more information. , and lawrenciumlawrencium, artificially produced radioactive chemical element; symbol Lr; at. no. 103; mass number of most stable isotope 262; m.p. about 1,627°C;; b.p. and sp. gr. unknown; valence +3. ..... Click the link for more information. . Thorium and uranium are the only actinides found in the earth's crust in appreciable quantities, although small amounts of neptunium and plutonium have been found in uranium ores. Actinium and protactinium are found in nature as decay products of some thorium and uranium isotopes. All the others have only been synthesized in small quantities (see synthetic elementssynthetic elements, in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no. ..... Click the link for more information. ). Study of the properties of the actinides is hampered by their radioactive instability. It is known, however, that all members of the series resemble actinium and each other in their chemical properties and that they have a strong chemical resemblance to their homologs in the lanthanide serieslanthanide series, BibliographySee A. J. Freeman and G. H. Lander, ed., Handbook on the Physics and Chemistry of the Actinides (1984); S. Cotton, Lanthanides and Actinides (1991). actinide series[′ak·tə‚nīd ′sir‚ēz]actinide seriesactinide series
Words related to actinide series
|
|||
随便看 |
|
英语词典包含2567994条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。