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词条 Isotopes of sodium
释义

  1. List of isotopes

      Notes  

  2. Sodium-24

  3. Sodium-22

  4. References

  5. External links

{{more footnotes|date=August 2017}}{{infobox sodium isotopes}}

There are 21 recognized isotopes of sodium (11Na), ranging from {{chem|18|Na}} to {{chem|39|Na}}[1] and two isomers ({{chem|22m|Na}} and {{chem|24m|Na}}). {{chem|23|Na}} is the only stable (and the only primordial) isotope. As such, it is considered a monoisotopic element and it has a standard atomic weight of {{val|22.98976928|(2)}}. Sodium has two radioactive cosmogenic isotopes ({{chem|22|Na}}, half-life = 2.605 years; and {{chem|link=Sodium-24|24|Na}}, half-life ≈ 15 hours). With the exception of those two, all other isotopes have half-lives under a minute, most under a second. The shortest-lived is {{chem|18|Na}}, with a half-life of {{val|1.3|(4)|e=-21}} seconds.

Acute neutron radiation exposure (e.g., from a nuclear criticality accident) converts some of the stable {{chem|23|Na}} in human blood plasma to {{chem|24|Na}}. By measuring the concentration of this isotope, the neutron radiation dosage to the victim can be computed.

{{chem|22|Na}} 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.

List of isotopes

nuclide
symbol		 Z(p) N(n)  
isotopic mass (u)[2]
 		half-lifedecay
mode(s)[3][4]		daughter
isotope(s)[5]		nuclear
spin and
parity		representative
isotopic
composition
(mole fraction)		range of natural
variation
(mole fraction)
excitation energy
18Na117{{val|18.02688|(10)}}{{val|1.3|(4)|e=-21|u=s}} p 17Ne(1−)#
β+ (<.1%) 18Ne
19Na11819.013880|(11)}}{{val>10|e=-18|u=s}} s p 18Ne (5/2+)
20Na119{{val|20.0073544|(12)}}447.9(23) ms β+ (75%) 20Ne2+
β+, α (25%) 16O
21Na111020.99765470|(11)}} 22.422(10) s β+ 21Ne 3/2+
22Na111121.99443742|(18)}} 2.6018(22) y β+ 22Ne 3+ Trace[6]
22m1Na583.03(9) keV 243(2) ns IT 22Na 1+
22m2Na657.00(14) keV 19.6(7) ps IT 22Na 0+
23Na111222.9897692820|(19)}}Stable 3/2+1.0000}}
24Na111323.990963011|(18)}}14.957|(4)|u=h}} β− 24Mg 4+ Trace[6]
24mNa472.207(9) keV20.18(10) ms IT (99.95%) 24Na1+
β− (.05%) 24Mg
25Na111424.9899540|(13)}} 59.1(6) s β− 25Mg 5/2+
26Na111525.992635|(4)}} 1.07128(25) s β− 26Mg 3+
26mNa82.5(6) keV 9(2) µs IT 26Na 1+
27Na1116{{val|26.994076|(4)}}301(6) ms β− (99.87%) 27Mg5/2+
β−, n (0.13%) 26Mg
28Na1117{{val|27.998939|(11)}}30.5(4) ms β− (99.42%) 28Mg1+
β−, n (0.58%) 27Mg
29Na1118{{val|29.002877|(8)}}44.1(9) ms β− (74.1%) 29Mg3/2(+#)
β−, n (25.9%) 28Mg
30Na1119{{val|30.009098|(5)}}48.4(17) ms β− (68.85%) 30Mg2+
β−, n (30.0%) 29Mg
β−, 2n (1.15%) 28Mg
β−, α (5.5×10-5%) 26Ne
31Na1120{{val|31.013147|(15)}}17.35(40) ms β− (61.78%) 31Mg(3/2+)
β−, n (37.3%) 30Mg
β−, 2n (0.87%) 29Mg
β−, 3n (0.05%) 28Mg
32Na1121{{val|32.02001|(4)}}12.9(3) ms β− (68%) 32Mg(3−)
β−, n (24%) 31Mg
β−, 2n (8%) 30Mg
33Na1122{{val|33.02553|(48)}}8.2(4) ms β−, n (47%) 32Mg(3/2+)
β− (40%) 33Mg
β−, 2n (13%) 31Mg
34Na1123{{val|34.03401|(64)}}5.5(10) ms β−, 2n (50.0%) 32Mg1+
β− (35.0%) 34Mg
β−, n (15.0%) 33Mg
35Na112435.04104|(72)}}# 1.5(5) ms β− 35Mg 3/2+#