Columbia Encyclopedia

Search results

500 results found

actinide series

(Encyclopedia)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 considered a...

oxidation and reduction

(Encyclopedia)oxidation and reduction, complementary chemical reactions characterized by the loss or gain, respectively, of one or more electrons by an atom or molecule. Originally the term oxidation was used to re...

versification

(Encyclopedia)versification, principles of metrical practice in poetry. In different literatures poetic form is achieved in various ways; usually, however, a definite and predictable pattern is evident in the langu...

electric circuit

(Encyclopedia)CE5 A. Series circuit: Current is the same through each resistance; voltage divides in direct proportion to each resistance. B. Parallel circuit: Voltage drop is the same over each resistance; curr...

aluminum

(Encyclopedia)aluminum ălˌyo͞omĭnˈēəm [key], metallic chemical element; symbol Al; at. no. 13; at. wt. 26.98154; m.p. 660.37℃; b.p. 2,467℃; sp. gr. 2.6989 at 20℃; valence +3. Aluminum is a silver-white...

income tax

(Encyclopedia)income tax, assessment levied upon individual or corporate incomes. Although personal incomes were occasionally taxed in medieval Italian cities, the income tax is essentially a modern form of taxatio...

nickel

(Encyclopedia)nickel, metallic chemical element; symbol Ni; at. no. 28; at. wt. 58.6934; m.p. about 1,453℃; b.p. about 2,732℃; sp. gr. 8.902 at 25℃; valence 0, +1, +2, +3, or +4. Nickel is a hard, malleable, ...

Pentecostalism

(Encyclopedia)Pentecostalism, worldwide 20th–21st-century Christian movement that emphasizes the experience of Spirit baptism, generally evidenced by speaking in tongues (glossolalia). The name derives from Pente...

Swabia

(Encyclopedia)Swabia swāˈbēə [key], Ger. Schwaben, historic region, mainly in S Baden-Württemberg and SW Bavaria, SW Germany. It is bounded in the east by Upper Bavaria, in the west by France, and in the south...

valence, in chemistry

(Encyclopedia)valence, combining capacity of an atom expressed as the number of single bonds the atom can form or the number of electrons an element gives up or accepts when reacting to form a compound. Atoms are c...