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- actinium series
Actinium series, natural radioactive decay series beginning with uranium-235 (also called actinouranium) and ending with lead-207. See radioactivity.
- Periodic Table of the Elements: Actinium
Periodic Table of the Elements: ActiniumAtomic Number:89Atomic Symbol:AcActiniumAtomic Weight:227.0278ElectronConfiguration:2 · 8 · 1832 · 189 · 2
- Ac, chemical symbol
Ac, symbol for the element actinium.
- actinide series
Actinide 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 cons...
- Meitner, Lise
Meitner, Lise, 1878–1968, Austrian-Swedish physicist and mathematician. She was professor at the Univ. of Berlin (1926–33). A refugee from Germany after 1938, she became associated with the Un...
- francium
Francium [from France], radioactive chemical element; symbol Fr; at. no. 87; mass no. of most stable isotope 223; m.p. about 27°C (estimated); b.p. 677°C (estimated); sp. gr. unknown; valence ...
- protactinium
Protactinium, radioactive chemical element; symbol Pa; at. no. 91; at. wt. 231.0359; m.p. greater than 1,600°C; b.p. 4,026°C; sp. gr. 15.37 (calculated); valence +4, +5. Protactinium is a mall...
- uranium
Uranium, radioactive metallic chemical element; symbol U; at. no. 92; at. wt. 238.0289; m.p. 1,132°C; b.p. 3,818°C; sp. gr. 19.1 at 25°C; valence +3, +4, +5, or +6. Uranium is a hard, dense, m...
- Elements (table)
ElementsElementSymbolAtomic NumberAtomic Weight1Melting Point(Degrees Celsius)Boiling Point(Degrees Celsius)1 Parentheses indicate most stable isotope.actiniumAc89227.02781050.3200....
