Sodium-20
Properties and data of the isotope 20Na.
Sodium-20 is a radioisotope of the chemical element sodium, which, in addition to the element-specific 11 protons, has 9 neutrons in the atomic nucleus, resulting in the mass number 20. The very short-lived, unstable and therefore radioactive nuclide, which can only be produced artificially, has no practical significance; The study of 20Na serves exclusively academic purposes.
The proton-rich isotope was first described in 1950 as a product of the irradiation of neon gas with protons (32 MeV) [1].
See also: List of individual Sodium isotopes (and general data sources).
General data
Name of the isotope:Sodium-20; Na-20Symbol:20Na or 2011NaMass number A:20 (= number of nucleons)Atomic number Z:11 (= number of protons)Neutrons N:9Isotopic mass:20.0073543(12) u (atomic weight of Sodium-20)Nuclide mass:20.00132 u (calculated nuclear mass without electrons)Mass excess:6.85049 MeVMass defect:0.156705296 u (per nucleus)Nuclear binding energy:145.97004299 MeV (per nucleus)
7.29850215 MeV (average binding energy per nucleon)Separation energy:SN = 14.150(11) MeV (first neutron)
SP = 2.1905(11) MeV (first proton)Half-life:447.9(23) msDecay constant λ:1.547548963072 s-1Specific activity α:4.659778921634 × 10+22 Bq g-1
1259399708549.8 Ci g-1Spin and parity:
(nuclear angular momentum)2+Isobaric spin: 1Magnetic dipole moment:μ(μN) = + 0.3694(2)Quadrupole moment Q:+0.101(8) barn (100 fm2)Nuclear g-factor:gl = 0.1847Charge radius:2.9718(420) femtometer fmMirror nucleus:Fluorine-20Year of discovery:1950
Radioactive Decay
Half-life T½ = 447.9(23) ms respectively 4.479 × 10-1 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| β+ | 20Ne | 75.0(4) % | 13.8924(11) MeV | |
| β+, α | 16O | 25.0(4) % | 9.160 MeV | |
Parent Nuclides
Direct parent isotope is: 20Mg.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 9) and isobaric (same nucleon number A = 20) with Sodium-20. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 9 | Isobar A = 20 |
|---|
| 3 | 12Li | |
| 4 | 13Be | |
| 5 | 14B | 20B |
| 6 | 15C | 20C |
| 7 | 16N | 20N |
| 8 | 17O | 20O |
| 9 | 18F | 20F |
| 10 | 19Ne | 20Ne |
| 11 | 20Na | 20Na |
| 12 | 21Mg | 20Mg |
| 13 | 22Al | 20Al |
| 14 | 23Si | |
| 15 | 24P | |
External data and identifiers
Literature and References
[1] - Luis W. Alvarez:
Three New Delayed Alpha-Emitters of Low Mass.
In: Physical Review, 80, 519, (1950), DOI 10.1103/PhysRev.80.519.
Last update: 2024-10-24
Perma link: https://www.chemlin.org/isotope/sodium-20
© 1996 - 2025 ChemLin
