Isotopes of magnesium
Encyclopedia
Magnesium
(Mg) naturally occurs in three stable isotopes, 24Mg, 25Mg, and 26Mg. 19 radioisotopes have been discovered, ranging from 19Mg to 40Mg. The longest-lived radioisotope is 28Mg with a half-life of 20.915 hours. The lighter isotopes mostly decay to isotopes of sodium
while the heavier isotopes decay to isotopes of aluminum. The shortest-lived is 39Mg with a half-life shorter than 180 nanoseconds, or rarely 40Mg, with a half-life longer than 170 nanoseconds (the half-life of 19Mg is unknown).
Standard atomic mass: 24.3050(6) u
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
(Mg) naturally occurs in three stable isotopes, 24Mg, 25Mg, and 26Mg. 19 radioisotopes have been discovered, ranging from 19Mg to 40Mg. The longest-lived radioisotope is 28Mg with a half-life of 20.915 hours. The lighter isotopes mostly decay to isotopes of sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
while the heavier isotopes decay to isotopes of aluminum. The shortest-lived is 39Mg with a half-life shorter than 180 nanoseconds, or rarely 40Mg, with a half-life longer than 170 nanoseconds (the half-life of 19Mg is unknown).
Standard atomic mass: 24.3050(6) u
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) |
|---|---|---|---|---|---|---|---|---|---|
| 19Mg | 12 | 7 | 19.03547(27) | 1/2-# | |||||
| 20Mg | 12 | 8 | 20.018863(29) | 90.8(24) 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... (97%) |
20Na | 0+ | ||
| β+, 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... (3%) |
19Ne | ||||||||
| 21Mg | 12 | 9 | 21.011713(18) | 122(2) ms | β+ (66.9%) | 21Na | (5/2,3/2)+ | ||
| β+, p (32.6%) | 20Ne | ||||||||
| 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... (0.5%) |
16F | ||||||||
| 22Mg | 12 | 10 | 21.9995738(14) | 3.8755(12) s | β+ | 22Na | 0+ | ||
| 23Mg | 12 | 11 | 22.9941237(14) | 11.317(11) s | β+ | 23Na | 3/2+ | ||
| 24Mg | 12 | 12 | 23.985041700(14) | Stable | 0+ | 0.7899(4) | 0.78958-0.79017 | ||
| 25Mg | 12 | 13 | 24.98583692(3) | Stable | 5/2+ | 0.1000(1) | 0.09996-0.10012 | ||
| 26MgUsed in radiodating events early in the Solar System's history | 12 | 14 | 25.982592929(30) | Stable | 0+ | 0.1101(3) | 0.10987-0.11030 | ||
| 27Mg | 12 | 15 | 26.98434059(5) | 9.458(12) min | β− | 27Al | 1/2+ | ||
| 28Mg | 12 | 16 | 27.9838768(22) | 20.915(9) h | β− | 28Al | 0+ | ||
| 29Mg | 12 | 17 | 28.988600(15) | 1.30(12) s | β− | 29Al | 3/2+ | ||
| 30Mg | 12 | 18 | 29.990434(9) | 335(17) ms | β− (99.94%) | 30Al | 0+ | ||
| β−, n Neutron emission Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13... (.06%) |
29Al | ||||||||
| 31Mg | 12 | 19 | 30.996546(13) | 230(20) ms | β− (98.3%) | 31Al | 3/2+ | ||
| β−, n (1.7%) | 30Al | ||||||||
| 32Mg | 12 | 20 | 31.998975(19) | 86(5) ms | β− (97.6%) | 32Al | 0+ | ||
| β−, n (2.4%) | 31Al | ||||||||
| 33Mg | 12 | 21 | 33.005254(21) | 90.5(16) ms | β− (83%) | 33Al | 7/2-# | ||
| β−, n (17%) | 32Al | ||||||||
| 34Mg | 12 | 22 | 34.00946(25) | 20(10) ms | β− (>99.9%) | 34Al | 0+ | ||
| β−, n (<.1%) | 33Al | ||||||||
| 35Mg | 12 | 23 | 35.01734(43)# | 70(40) ms | β−, n (52%) | 34Al | (7/2-)# | ||
| β− (48%) | 35Al | ||||||||
| 36Mg | 12 | 24 | 36.02300(54)# | 3.9(13) ms | β− | 36Al | 0+ | ||
| 37Mg | 12 | 25 | 37.03140(97)# | 40# ms [>260 ns] | β− | 37Al | 7/2-# | ||
| β−, n | 36Al | ||||||||
| 38Mg | 12 | 26 | 38.03757(54)# | 1# ms [>260 ns] | 0+ | ||||
| 39Mg | 12 | 27 | 39.04677(55)# | <260 ns | 7/2-# | ||||
| 40Mg | 12 | 28 | 40.05393(97)# | 1# ms | 0+ | ||||