Neutron number

Neutron number

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.

Neutron number is rarely written explicitly in nuclide symbol notation, but appears as a subscript to the right of the element symbol. In order of increasing explicitness and decreasing frequency of usage:

Element C
Isotope/Nuclide 14
C
With atomic number 14
6
C
With neutron number 14
6
C
8

Nuclides that have the same neutron number but a different proton number are called isotones. This word was formed by replacing the p in isotope with n for neutron. Nuclides that have the same mass number are called isobars.

Chemical properties are primarily determined by proton number, which determines which chemical element the nuclide is a member of; neutron number has only a slight influence.

Neutron number is primarily of interest for nuclear properties. For example, actinides with odd neutron number are usually fissile (fissionable with slow neutrons) while actinides with even neutron number are usually not fissile (but are fissionable with fast neutrons).

Only 58 stable nuclides have odd neutron number, compared to 200 with even neutron number. No odd-neutron-number isotope is the most naturally abundant isotope in its element, except for beryllium-9 which is the only stable beryllium isotope, nitrogen-14, and platinum-195.


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • neutron number — n. the number of neutrons in a given nucleus: it is the difference between the mass number and the atomic number …   English World dictionary

  • neutron number — Physics. the number of neutrons in the nucleus of an atom, equal to the mass number minus the atomic number of the atom. Symbol: N [1950 55] * * * neutron number noun The number of neutrons in the nucleus of an atom • • • Main Entry: ↑neutron …   Useful english dictionary

  • neutron number — neutronų skaičius statusas T sritis Standartizacija ir metrologija apibrėžtis Neutronų skaičius atomo branduolyje. atitikmenys: angl. neutron number vok. Neutronenzahl, f rus. число нейтронов, n pranc. nombre de neutrons, m …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • neutron number — neutronų skaičius statusas T sritis fizika atitikmenys: angl. neutron number vok. Neutronenzahl, f rus. число нейтронов, n pranc. nombre de neutrons, m; nombre neutronique, m …   Fizikos terminų žodynas

  • neutron number — Physics. the number of neutrons in the nucleus of an atom, equal to the mass number minus the atomic number of the atom. Symbol: N [1950 55] * * * …   Universalium

  • neutron number — (N) the number of neutrons in a nucleus, representing the difference between the mass number and the atomic number …   Medical dictionary

  • neutron number — noun The number of neutrons in the nucleus of an atom or isotope …   Wiktionary

  • neutron number density — neutronų tankis statusas T sritis Standartizacija ir metrologija apibrėžtis Tūrio elemente esančių laisvųjų neutronų skaičius, padalytas iš to tūrio. atitikmenys: angl. neutron number density vok. Neutronendichte, f; Neutronenzahldichte, f rus.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • diffusion coefficient for neutron number density — neutronų difuzijos koeficientas statusas T sritis Standartizacija ir metrologija apibrėžtis Apibrėžtį žr. priede. priedas( ai) Grafinis formatas atitikmenys: angl. diffusion coefficient for neutron number density rus. коэффициент диффузии для… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

  • diffusion coefficient for neutron number density — neutronų difuzijos koeficientas statusas T sritis fizika atitikmenys: angl. diffusion coefficient for neutron number density vok. Diffusionskoeffizient für Neutronenflußdichte, m rus. коэффициент диффузии для плотности нейтронов, m pranc.… …   Fizikos terminų žodynas

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”