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tennessine

(Encyclopedia)tennessine tĕnˈəsēn [key], artificially produced radioactive chemical element; symbol Ts; at. no. 117; mass number of most stable isotope 294; m.p., b.p., sp. gr., and valence unknown. Tennessine ...

rhenium

(Encyclopedia)rhenium rēˈnēəm [key], metallic chemical element; symbol Re; at. no. 75; at. wt. 186.207; m.p. about 3,180℃; b.p. about 5,625℃; sp. gr. 21.02 at 20℃; valence −1, +2, +3, +4, +5, +6, or +7....

halogen

(Encyclopedia)halogen hălˈəjĕn [key] [Gr.,=salt-bearing], any of the chemically active elements found in Group 17 of the periodic table; the name applies especially to fluorine (symbol F), chlorine (Cl), bromin...

lawrencium

(Encyclopedia)lawrencium, artificially produced radioactive chemical element; symbol Lr; at. no. 103; mass number of most stable isotope 262; m.p. about 1,627℃; b.p. and sp. gr. unknown; valence +3. Lawrencium is...

livermorium

(Encyclopedia)livermorium, artificially produced radioactive chemical element; symbol Lv; at. no. 116; mass number of most stable isotope 292; m.p., b.p., sp. gr., and valence unknown. Situated in Group 16 of the p...

silver

(Encyclopedia)silver, metallic chemical element; symbol Ag [Lat. argentum]; at. no. 47; at. wt. 107.8682; m.p. 961.93℃; b.p. 2,212℃; sp. gr. 10.5 at 20℃; valence +1 or +2. Pure silver is nearly white, lustrou...

synthetic elements

(Encyclopedia)synthetic 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...

Emirates of the South, Federation of the

(Encyclopedia)Emirates of the South, Federation of the: see South Arabia, Federation of. ...

Federation of the Emirates of the South

(Encyclopedia)Federation of the Emirates of the South: see South Arabia, Federation of. ...

seaborgium

(Encyclopedia)seaborgium sēbôrˈgēəm [key], artificially produced radioactive chemical element; symbol Sg; at. no. 106; mass number of most stable isotope 271; m.p., b.p., sp. gr., and valence unknown. Situated...