mass number


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Related to mass number: Isotopy

number

 [num´ber]
a symbol, as a figure or word, expressive of a certain value or a specified quantity determined by count.
atomic number (Z) a number expressive of the number of protons in an atomic nucleus, or the positive charge of the nucleus expressed in terms of the electronic charge.
Avogadro's number (N) (NA) the number of molecules in one mole of a substance: 6.023 × 1023. Called also Avogadro's constant.
CT number the density assigned to a voxel in a CAT scan on an arbitrary scale on which air has a density −1000; water, 0; and compact bone +1000. See also hounsfield unit.
mass number (A) the number of nucleons (protons plus neutrons) in the atom of a nuclide; generally indicated by a superscript preceding the symbol of a chemical element (e.g., 131I), denoting a specific isotope.
oxidation number a number assigned to each atom in a molecule or ion that represents the number of electrons theoretically gained (positive oxidation numbers) or lost (negative numbers) in converting the atom to the elemental form.

mass num·ber

the mass of the atom of a particular isotope relative to hydrogen-1 (or to 1/12 the mass of carbon 12); generally very close to the whole number represented by the sum of the protons and neutrons in the atomic nucleus of the isotope (indicated in the name or symbol of the isotope, for example, oxygen-16, 16O); not to be confused with the atomic weight of an element, which may include a number of isotopes in their natural proportion.

mass number

The number of protons and neutrons in a nuclide (e.g., 14 in 14C).

mass num·ber

(mas nŭmbĕr)
Atomic mass of a particular isotope relative to hydrogen-1 (or to 1/12 the mass of carbon 12); generally very close to the whole number represented by the sum of the protons and neutrons in the atomic nucleus of the isotope (indicated in the name or symbol of the isotope, e.g., oxygen-16, 16O); not to be confused with the atomic weight of an element, which may include a number of isotopes in their natural proportion.
References in periodicals archive ?
From Figures 1 and 2, we may see that the total nuclear reaction cross section with and without nuclear medium effect increases with the mass number of target nucleus, in case of all considered projectiles.
Differences among crosses were expected since parents varying in gall number and egg mass number were purposefully selected.
5 shows an empirical dependency between the radius of a nucleus and the number of nucleons in it (mass number).
This method has to be analyzed and extended for isotopes above and below the stable mass number [A.sub.S] of any Z value.
A section of FIONA then uses crossed electric and magnetic fields to select the heavy elements by mass number before they are implanted into a sensitive silicon-based detector array that can measure the energy, position and timing of the decay of radioactive atoms.
In this theory, the elastic scattering amplitude between deuteron of mass number A and a target nucleus of mass number B and atomic number [Z.sub.B] is given as [16]
A nuclide is that version of an atom defined by its mass number (A = Z + N), its atomic number (Z) and a power condition of its nucleus.
According to the new pact, pilgrims from Iran who travel to Iraq in mass numbers in days before and after Arbaeen, which will fall in late October this year, would be allowed to enter Iraq without obtaining visas.
Everybody is stressed because there are these mass numbers of people."
He concluded by saying that 'the days of the corrupt PDP in Enugu are long gone as the people have taken a stance for integrity and progress the APC espouses as seen in the unprecedented mass numbers that trooped out to receive President Buhari on his recent visit to the state.
Less often, but with more notice taken, they are used to mow down mass numbers of people, as occurred on Wednesday night here in California, which has some of the toughest gun control laws in the nation.
While the initiative is a positive step towards reducing emissions levels, our members are concerned that electricity supply to commercial premises needs to be improved if mass numbers of vans are to be able to convert to electric.