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The neutron number (symbol N) is the number of neutrons in a nuclide. Atomic number (proton number) plus neutron number equals mass number: Z + N = A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N − Z = A − 2Z. Neutron number is not written explicitly in nuclide symbol notation, but ...
The electron configuration is determined by the charge of the nucleus, which is determined by the number of protons, or atomic number. The number of neutrons is the neutron number. Neutrons do not affect the electron configuration. Atoms of a chemical element that differ only in neutron number are called isotopes.
Using the number density as a function of spatial coordinates, the total number of objects N in the entire volume V can be calculated as = (,,), where dV = dx dy dz is a volume element. If each object possesses the same mass m 0 , the total mass m of all the objects in the volume V can be expressed as m = ∭ V m 0 n ( x , y , z ) d V ...
The mass number is different for each isotope of a given chemical element, and the difference between the mass number and the atomic number Z gives the number of neutrons (N) in the nucleus: N = A − Z. [2] The mass number is written either after the element name or as a superscript to the left of an element's symbol.
Nuclides with mass number greater than 64 are predominantly produced by neutron capture processes—the s-process and r-process–in supernova explosions and neutron star mergers. The Solar System is thought to have condensed approximately 4.6 billion years before the present, from a cloud of hydrogen and helium containing heavier elements in ...
The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of its atomic nucleus. For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (n p) or the number of protons found in the nucleus of every atom of that element.
The mass number of an element, A, is the number of nucleons (protons and neutrons) in the atomic nucleus. Different isotopes of a given element are distinguished by their mass number, which is written as a superscript on the left hand side of the chemical symbol (e.g., 238 U). The mass number is always an integer and has units of "nucleons".
Actinides with odd neutron numbers are generally fissile (with thermal neutrons), while those with even neutron numbers are generally not, though they are fissionable with fast neutrons. Only 9 4 Be, 14 7 N, and 195 78 Pt have an odd neutron number and are the most naturally abundant isotope of their element.