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Johnson, Sir William

(Encyclopedia)Johnson, Sir William, 1715–74, British colonial leader in America, b. Co. Meath, Ireland. He settled (1738) in the Mohawk valley, became a merchant, and gained great power among the Mohawk and other...

glycoprotein

(Encyclopedia)glycoprotein glīˌkōprōˈtēn [key], organic compound composed of both a protein and a carbohydrate joined together in covalent chemical linkage. These structures occur in many life forms; they are...

alkaloid

(Encyclopedia)alkaloid, any of a class of organic compounds composed of carbon, hydrogen, nitrogen, and usually oxygen that are often derived from plants. Although the name means alkalilike, some alkaloids do not e...

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...

neutron

(Encyclopedia)neutron, uncharged elementary particle of slightly greater mass than the proton. It was discovered by James Chadwick in 1932. The stable isotopes of all elements except hydrogen and helium contain a n...

radon

(Encyclopedia)radon rāˈdŏn [key], gaseous radioactive chemical element; symbol Rn; at. no. 86; mass no. of most stable isotope 222; m.p. about −71℃; b.p. −61.8℃; density 9.73 grams per liter at STP; vale...

sponge

(Encyclopedia)sponge, common name for members of the aquatic animal phylum Porifera, and for the dried, processed skeletons of certain species used to hold water. Over 4,500 living species are known; they are found...

technetium

(Encyclopedia)technetium tĕknēˈshēəm [key] [Gr. technetos=artificial], artificially produced radioactive chemical element; symbol Tc; at. no. 43; mass no. of most stable isotope 98; m.p. 2,200℃; b.p. 4,877�...

Cárdenas, Lázaro

(Encyclopedia)Cárdenas, Lázaro ko͞o-outāˈmôk, sōlôrˈsänō [key], 1934–, seen since the 1980s as his father's political heir, held posts within the ruling Institutional Revolutionary party (PRI) before 1...

moscovium

(Encyclopedia)moscovium mŏskōˈvēəm [key], artificially produced radioactive chemical element; symbol Mc; at. no. 115; mass number of most stable isotope 288; m.p., b.p., sp. gr., and valence unknown. Situated ...