Isotopes of nitrogen
Encyclopedia
Natural Nitrogen
(N) consists of two stable isotopes, nitrogen-14, which makes up the vast majority of naturally occurring nitrogen, and nitrogen-15. Fourteen radioactive isotopes (radioisotopes) have also been found so far, with atomic mass
es ranging from 10 to 25, and one nuclear isomer
, 11mN. All of these radioisotopes are short-lived, with the longest-lived one being nitrogen-13 with a half-life of 9.965 minutes. All of the others have half-lives below 7.15 seconds, with most of these being below five-eighths of a second. Most of the isotopes with atomic mass numbers below 14 decay to isotopes of carbon
, while most of the isotopes with masses above 15 decay to isotopes of oxygen
. The shortest-lived known isotope is nitrogen-10, with a half-life of abut 2.3 microsecond
s.
The standard atomic mass of nitrogen is 14.0067 atomic mass units.
(non-radioactive) isotope
s of the chemical element
nitrogen
, which maked up about 99.636% of natural nitrogen.
Nitrogen-14 is one of the very few stable nuclides with both an odd number of protons and of neutrons (seven each). Each of these contributes a nucler spin
of plus of minus spin 1/2, giving the nucleus a total magnetic spin
of one.
Like all elements heavier than lithium
, the original source of nitrogen-14 and nitrogen-15 in the Universe
is believed to be stellar nucleosynthesis
, where they are produced as part of the carbon-nitrogen-oxygen cycle.
Nitrogen-14 is the source of naturally-occurring carbon-14
. Some kinds of cosmic radiation causes a nuclear reaction
with nitrogen-14 in the upper atmosphere of the Earth, creating the carbon-14. This radioisotope decays back to nitrogen-14 after a half-life
of several thousand years.
of nitrogen
. This istope is often used in agricultural
and medical
research, for example in the Meselson–Stahl experiment to establish the nature of DNA replication
. An extension of this research resulted in development of DNA-based stable-isotope probing, which allows examination of links between metabolic function and taxonomic identity of microorganisms in the environment, without the need for culture isolation. Nitrogen-15 is extensively used to trace mineral nitrogen compounds (particularly fertilizers) in the environment and when combined with the use of other isotopic labels, is also a very important tracer for describing the fate of nitrogenous organic pollutants.
Nitrogen-15 is frequently used in nuclear magnetic resonance spectroscopy (NMR), because unlike the more abundant splinless nitrogen-14, it has a fractional nuclear
spin
of one-half, which makes it observatable by NMR. Protein
s can be isotopically labelled by cultivating them in a medium containing nitrogen-15 as the only source of nitrogen. In addition, nitrogen-15 is used to label proteins in quantitative proteomics
(e.g. SILAC
).
Two sourses of nitrogen-15 is by the positron emission
of oxygen-15 and the beta decay
of carbon-15.
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
(N) consists of two stable isotopes, nitrogen-14, which makes up the vast majority of naturally occurring nitrogen, and nitrogen-15. Fourteen radioactive isotopes (radioisotopes) have also been found so far, with atomic mass
Atomic mass
The atomic mass is the mass of a specific isotope, most often expressed in unified atomic mass units. The atomic mass is the total mass of protons, neutrons and electrons in a single atom....
es ranging from 10 to 25, and one nuclear isomer
Nuclear isomer
A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons . "Metastable" refers to the fact that these excited states have half-lives more than 100 to 1000 times the half-lives of the other possible excited nuclear states...
, 11mN. All of these radioisotopes are short-lived, with the longest-lived one being nitrogen-13 with a half-life of 9.965 minutes. All of the others have half-lives below 7.15 seconds, with most of these being below five-eighths of a second. Most of the isotopes with atomic mass numbers below 14 decay to isotopes of carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
, while most of the isotopes with masses above 15 decay to isotopes of oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
. The shortest-lived known isotope is nitrogen-10, with a half-life of abut 2.3 microsecond
Microsecond
A microsecond is an SI unit of time equal to one millionth of a second. Its symbol is µs.A microsecond is equal to 1000 nanoseconds or 1/1000 millisecond...
s.
The standard atomic mass of nitrogen is 14.0067 atomic mass units.
Nitrogen-14
Nitrogen-14 is one of two stableStable isotope
Stable isotopes are chemical isotopes that may or may not be radioactive, but if radioactive, have half-lives too long to be measured.Only 90 nuclides from the first 40 elements are energetically stable to any kind of decay save proton decay, in theory...
(non-radioactive) isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s of the chemical element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, which maked up about 99.636% of natural nitrogen.
Nitrogen-14 is one of the very few stable nuclides with both an odd number of protons and of neutrons (seven each). Each of these contributes a nucler spin
Spin (physics)
In quantum mechanics and particle physics, spin is a fundamental characteristic property of elementary particles, composite particles , and atomic nuclei.It is worth noting that the intrinsic property of subatomic particles called spin and discussed in this article, is related in some small ways,...
of plus of minus spin 1/2, giving the nucleus a total magnetic spin
Spin (physics)
In quantum mechanics and particle physics, spin is a fundamental characteristic property of elementary particles, composite particles , and atomic nuclei.It is worth noting that the intrinsic property of subatomic particles called spin and discussed in this article, is related in some small ways,...
of one.
Like all elements heavier than lithium
Lithium
Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly...
, the original source of nitrogen-14 and nitrogen-15 in the Universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
is believed to be stellar nucleosynthesis
Stellar nucleosynthesis
Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the elements heavier than hydrogen. Some small quantity of these reactions also occur on the stellar surface under various circumstances...
, where they are produced as part of the carbon-nitrogen-oxygen cycle.
Nitrogen-14 is the source of naturally-occurring carbon-14
Carbon-14
Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with a nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues , to date archaeological, geological, and hydrogeological...
. Some kinds of cosmic radiation causes a nuclear reaction
Nuclear reaction
In nuclear physics and nuclear chemistry, a nuclear reaction is semantically considered to be the process in which two nuclei, or else a nucleus of an atom and a subatomic particle from outside the atom, collide to produce products different from the initial particles...
with nitrogen-14 in the upper atmosphere of the Earth, creating the carbon-14. This radioisotope decays back to nitrogen-14 after a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of several thousand years.
Nitrogen-15
Nitrogen-15 is a rare stable isotopeIsotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
of nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
. This istope is often used in agricultural
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
and medical
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
research, for example in the Meselson–Stahl experiment to establish the nature of DNA replication
DNA replication
DNA replication is a biological process that occurs in all living organisms and copies their DNA; it is the basis for biological inheritance. The process starts with one double-stranded DNA molecule and produces two identical copies of the molecule...
. An extension of this research resulted in development of DNA-based stable-isotope probing, which allows examination of links between metabolic function and taxonomic identity of microorganisms in the environment, without the need for culture isolation. Nitrogen-15 is extensively used to trace mineral nitrogen compounds (particularly fertilizers) in the environment and when combined with the use of other isotopic labels, is also a very important tracer for describing the fate of nitrogenous organic pollutants.
Nitrogen-15 is frequently used in nuclear magnetic resonance spectroscopy (NMR), because unlike the more abundant splinless nitrogen-14, it has a fractional nuclear
Atomic nucleus
The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The...
spin
Spin (physics)
In quantum mechanics and particle physics, spin is a fundamental characteristic property of elementary particles, composite particles , and atomic nuclei.It is worth noting that the intrinsic property of subatomic particles called spin and discussed in this article, is related in some small ways,...
of one-half, which makes it observatable by NMR. Protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s can be isotopically labelled by cultivating them in a medium containing nitrogen-15 as the only source of nitrogen. In addition, nitrogen-15 is used to label proteins in quantitative proteomics
Proteomics
Proteomics is the large-scale study of proteins, particularly their structures and functions. Proteins are vital parts of living organisms, as they are the main components of the physiological metabolic pathways of cells. The term "proteomics" was first coined in 1997 to make an analogy with...
(e.g. SILAC
Silac
SILAC is a technique based on mass spectrometry that detects differences in protein abundance among samples using non-radioactive isotopic labeling. It is a popular method for quantitative proteomics.-Procedure:Two populations of cells are cultivated in cell culture...
).
Two sourses of nitrogen-15 is by the positron emission
Positron emission
Positron emission or beta plus decay is a type of beta decay in which a proton is converted, via the weak force, to a neutron, releasing a positron and a neutrino....
of oxygen-15 and the beta decay
Beta decay
In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...
of carbon-15.
Table
| nuclide symbol |
Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... ) |
N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... ) |
isotopic mass (u) |
half-life | decay mode(s) | daughter isotope(s)Bold for stable isotopes |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 10N | 7 | 3 | 10.04165(43) | 200(140) s [2.3(16) MeV] |
p Proton decay In particle physics, proton decay is a hypothetical form of radioactive decay in which the proton decays into lighter subatomic particles, such as a neutral pion and a positron... |
(2−) | |||
| 11N | 7 | 4 | 11.02609(5) | 590(210) s [1.58(+75−52) MeV] |
p | 1/2+ | |||
| 11mN | 740(60) keV | 6.90(80) s | 1/2− | ||||||
| 12N | 7 | 5 | 12.0186132(11) | 11.000(16) ms | β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a... (96.5%) |
1+ | |||
| β+, α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less... (3.5%) |
Immediately decays into two alpha particles for a net reaction of 12N -> 34He + e+ | ||||||||
| 13N Nitrogen-13 Nitrogen-13 is a radioisotope of nitrogen used in positron emission tomography . It has a half life of a little under ten minutes, so it must be made at the PET site... Used in positron emission tomography Positron emission tomography Positron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a... |
7 | 6 | 13.00573861(29) | 9.965(4) min | β+ | 1/2− | |||
| 14N | 7 | 7 | 14.0030740048(6) | Stable | 1+ | 0.99636(20) | 0.99579–0.99654 | ||
| 15N | 7 | 8 | 15.0001088982(7) | Stable | 1/2− | 0.00364(20) | 0.00346–0.00421 | ||
| 16N | 7 | 9 | 16.0061017(28) | 7.13(2) s | β− (99.99%) | 2− | |||
| β−, α (.001%) | |||||||||
| 17N | 7 | 10 | 17.008450(16) | 4.173(4) s | β−, n (95.0%) | 1/2− | |||
| β− (4.99%) | |||||||||
| β−, α (.0025%) | |||||||||
| 18N | 7 | 11 | 18.014079(20) | 622(9) ms | β− (76.9%) | 1− | |||
| β−, α (12.2%) | |||||||||
| β−, n (10.9%) | |||||||||
| 19N | 7 | 12 | 19.017029(18) | 271(8) ms | β−, n (54.6%) | (1/2−) | |||
| β− (45.4%) | |||||||||
| 20N | 7 | 13 | 20.02337(6) | 130(7) ms | β−, n (56.99%) | 19O | |||
| β− (43.00%) | 20O | ||||||||
| 21N | 7 | 14 | 21.02711(10) | 87(6) ms | β−, n (80.0%) | 20O | 1/2−# | ||
| β− (20.0%) | 21O | ||||||||
| 22N | 7 | 15 | 22.03439(21) | 13.9(14) ms | β− (65.0%) | 22O | |||
| β−, n (35.0%) | 21O | ||||||||
| 23N | 7 | 16 | 23.04122(32)# | 14.5(24) ms [14.1(+12−15) ms] |
β− | 23O | 1/2−# | ||
| 24N | 7 | 17 | 24.05104(43)# | <52 ns | n | 23N | |||
| 25N | 7 | 18 | 25.06066(54)# | <260 ns | 1/2−# | ||||