A highly unstable radioactive element, the heaviest of the halogen group, that resembles iodine in solution. Its longest lived isotope has a mass number of 210 and has a half-life of 8.3 hours. Atomic number 85; melting point 302°C; boiling point 337°C; valence probably 1, 3, 5, 7.
(Mathematics) A set with an operation whose domain is all ordered pairs of members of the set, such that the operation is binary (operates on two elements) and associative, the set contains the identity element of the operation, and each element of the set has an inverse element for the operation. The positive and negative integers and zero form a set that is a group under the operation of ordinary addition, since zero is the identity element of addition and the negative of each integer is its inverse. Groups are used extensively in quantum physics and chemistry to model phenomena involving symmetry and invariance.
Material is defined as the physical components of something, to relevant facts, to jokes or items that are part of a performers routine, or to the things required to build something or accomplish a task.
Any of a category of electropositive elements that usually have a shiny surface, are generally good conductors of heat and electricity, and can be melted or fused, hammered into thin sheets, or drawn into wires. Typical metals form salts with nonmetals, basic oxides with oxygen, and alloys with one another.
A colorless, odorless compound of hydrogen and oxygen. Water covers about three-quarters of the Earth's surface in solid form (ice) and liquid form, and is prevalent in the lower atmosphere in its gaseous form, water vapor. Water is an unusually good solvent for a large variety of substances, and is an essential component of all organisms, being necessary for most biological processes. Unlike most substances, water is less dense as ice than in liquid form; thus, ice floats on liquid water. Water freezes at 0°C (32°F) and boils at 100°C (212°F). Chemical formula:H2O.
A table in which the chemical elements are arranged in order of increasing atomic number. Elements with similar properties are arranged in the same column (called a group), and elements with the same number of electron shells are arranged in the same row (called a period).
SymbolAm A synthetic, silvery-white, radioactive metallic element of the actinide series that is produced artificially by bombarding plutonium with neutrons. Americium is used as a source of alpha particles for smoke detectors and gamma rays for industrial gauges. Its most stable isotope has a half-life of 7,950 years. Atomic number 95; specific gravity 11.7; valence 3, 4, 5, 6.
A synthetic transuranic radioactive element having isotopes with mass numbers from 235 to 254. Its longest-lived isotopes, Bk-247 and Bk-248, have half-lives of 1,380 years and more than 9 years, respectively; the isotope produced in greatest quantity, Bk-249, has a half-life of 330 days. Atomic number 97; melting point 996°C; specific gravity 14 (estimated); valence 3, 4.
A synthetic, silvery-white, radioactive metallic element of the actinide series that is produced artificially from plutonium or americium. Curium isotopes are used to provide electricity for satellites and space probes. Its most stable isotope has a half-life of 16.4 million years. Atomic number 96; melting point (estimated) 1,350°C; valence 3.
A synthetic, radioactive metallic element of the actinide series that is usually produced by bombarding plutonium or another element with neutrons. It was first isolated in a region near the explosion site of a hydrogen bomb. Its longest-lived isotope is Es 254 with a half-life of 276 days. Atomic number 99; melting point 860°C.
An extremely unstable, radioactive element of the alkali group. It is the heaviest metal of the group. Francium occurs in nature, but less than 28.35 g (1 oz) is present in the Earth's crust at any time. It has approximately 19 isotopes, the most stable of which is Fr 223 with a half-life of 21 minutes. Atomic number 87; valence 1.
A radioactive metallic element, occurring naturally in small quantities as a product of radium disintegration and produced synthetically by bombarding bismuth or lead with neutrons. Most isotopes decay by alpha-particle emission; the most stable are Po-208 and Po-209, with half-lives of 2.9 years and 102 years, respectively. Po-210, with a half-life of 138.4 days, is the most readily available isotope and is extremely toxic. Atomic number 84; melting point 254°C; boiling point 962°C; specific gravity 9.20; valence 2, 4, 6.
A radioactive rare-earth element prepared by fission of uranium or by neutron bombardment of neodymium, having nearly 50 isotopes and isomers, of which the most stable have half-lives of 2.62 years (Pm-147), 5.53 years (Pm-146), and 17.7 years (Pm-145). Promethium-147 is most easily obtained and is used as a source of beta rays. Atomic number 61; melting point 1,042°C; boiling point 3000°C; specific gravity 7.264 (25°C); valence 3.
A rare, extremely toxic, radioactive metallic element of the actinide series that occurs in uranium ores. It has 13 known isotopes, the most stable of which is protactinium 231 with a half-life of 32,760 years. Atomic number 91; approximate melting point 1,550°C; specific gravity 15.37; valence 4, 5.
A silvery-gray radioactive metal, the first synthetically produced element, having isotopes with masses ranging from 85 to 118 and half-lives up to 4.2 million years. It is principally used as a tracer in a variety of medical applications. It is a remarkable inhibitor of corrosion in steel, but this use is limited because of radioactivity hazards. Atomic number 43; melting point 2,157°C; boiling point 4,265°C; specific gravity 11.50 (calculated); valence 0, 2, 4, 5, 6, 7.
A very hard, heavy, silver-colored, radioactive, metallic chemical element, one of the actinides, found only in combination, chiefly in pitchblende: symbol, U; at. no. 92: an isotope (uranium-235) undergoes neutron-induced fission and another, more plentiful, isotope (uranium-238) is used to produce plutonium
applies to any of the component parts that are instrumental in determining the nature of the complex luck was a factor in his success
refers to any of the substances (sometimes nonessential) that are mixed together in preparing a food, medicine, etc. the ingredients of a cocktail
both refer to any of the simple or compound parts of some complex thing or concept, but constituent also implies that the part is essential to the complex hemoglobin is a constituent of blood
, in its general use, is the broadest term for any of the basic, irreducible parts or principles of anything, concrete or abstract the elements of a science
Find another word for element. In this page you can discover 88 synonyms, antonyms, idiomatic expressions, and related words for element, like: ultimate, component, fundamental, constituent, factor, portion, astatine, ingredient, particle, elemental and aspect.