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There are thirteen recognized isotopes of sodium. 23Na is the only stable isotope. As such, it is considered a monoisotopic element and it has a standard atomic mass: 22.98976928(2) u. Sodium has two radioactive cosmogenic isotopes (22Na, half-life = 2.605 years; and 24Na, half-life 15 hours).
Acute neutron radiation exposure (e.g., from a nuclear criticality accident) converts some of the stable 23Na in human blood plasma to 24Na. By measuring the concentration of this isotope, the neutron radiation dosage to the victim can be computed.
22Na is a positron-emitting isotope with a remarkably long half-life. It is used to create test-objects and point-sources for Positron emission tomography.
Table
nuclide
symbol |
Z(p) |
N(n) |
isotopic mass (u)
|
half-life |
nuclear
spin |
representative
isotopic
composition
(mole fraction) |
range of natural
variation
(mole fraction) |
| excitation energy |
| 18Na |
11 |
7 |
18.02597(5) |
1.3(4)E-21 s |
(1-)# |
|
|
| 19Na |
11 |
8 |
19.013877(13) |
<40 ns |
(5/2+)# |
|
|
| 20Na |
11 |
9 |
20.007351(7) |
447.9(23) ms |
2+ |
|
|
| 21Na |
11 |
10 |
20.9976552(8) |
22.49(4) s |
3/2+ |
|
|
| 22Na |
11 |
11 |
21.9944364(4) |
2.6027(10) yr |
3+ |
|
|
| 22mNa |
583.03(9) keV |
244(6) ns |
1+ |
|
|
| 23Na |
11 |
12 |
22.9897692809(29) |
STABLE |
3/2+ |
1.0000 |
|
| 24Na |
11 |
13 |
23.99096278(8) |
14.9590(12) h |
4+ |
|
|
| 24mNa |
472.207(9) keV |
20.20(7) ms |
1+ |
|
|
| 25Na |
11 |
14 |
24.9899540(13) |
59.1(6) s |
5/2+ |
|
|
| 26Na |
11 |
15 |
25.992633(6) |
1.077(5) s |
3+ |
|
|
| 27Na |
11 |
16 |
26.994077(4) |
301(6) ms |
5/2+ |
|
|
| 28Na |
11 |
17 |
27.998938(14) |
30.5(4) ms |
1+ |
|
|
| 29Na |
11 |
18 |
29.002861(14) |
44.9(12) ms |
3/2(+#) |
|
|
| 30Na |
11 |
19 |
30.008976(27) |
48.4(17) ms |
2+ |
|
|
| 31Na |
11 |
20 |
31.01359(23) |
17.0(4) ms |
(3/2+) |
|
|
| 32Na |
11 |
21 |
32.02047(38) |
12.9(7) ms |
(3-,4-) |
|
|
| 33Na |
11 |
22 |
33.02672(94) |
8.2(2) ms |
3/2+# |
|
|
| 34Na |
11 |
23 |
34.03517(96)# |
5.5(10) ms |
1+ |
|
|
| 35Na |
11 |
24 |
35.04249(102)# |
1.5(5) ms |
3/2+# |
|
|
| 36Na |
11 |
25 |
36.05148(102)# |
<260 ns |
|
|
|
| 37Na |
11 |
26 |
37.05934(103)# |
1# ms [>1.5 ľs] |
3/2+# |
|
|
Notes
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.
References
- Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
- Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
- Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
- Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
- National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
- David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.
External links
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