Oxygen-20

Properties and data of the isotope ²⁰O.

Content

General data

Name of the isotope:Oxygen-20; O-20Symbol:²⁰O or 208OMass number A:20 (= number of nucleons)Atomic number Z:8 (= number of protons)Neutrons N:12Isotopic mass:20.0040754(9) u (atomic weight of Oxygen-20)Nuclide mass:19.9996868 u (calculated nuclear mass without electrons)Mass excess:3.79621 MeVMass defect:0.162503848 u (per nucleus)Nuclear binding energy:151.37135939 MeV (per nucleus)
7.56856797 MeV (average binding energy per nucleon)Separation energy:S_N = 7.6080(28) MeV (first neutron)
S_P = 19.349(16) MeV (first proton)Half-life:13.51(5) sDecay constant λ:0.051306230981491 s^-1Specific activity α:1.54486674981 × 10⁺²¹ Bq g^-1
41753155400.405 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Isobaric spin: 2Mirror nucleus:Magnesium-20Year of discovery:1959

Radioactive Decay

Half-life T_½ = 13.51(5) s respectively 1.351 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁰F	100 %	3.8136(9) MeV

Parent Nuclides

Direct parent isotopes are: ²⁰N, ²¹N.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 12) and isobaric (same nucleon number A = 20) with Oxygen-20. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 12	Isobar A = 20
4	¹⁶Be
5	¹⁷B	²⁰B
6	¹⁸C	²⁰C
7	¹⁹N	²⁰N
8	²⁰O	²⁰O
9	²¹F	²⁰F
10	²²Ne	²⁰Ne
11	²³Na	²⁰Na
12	²⁴Mg	²⁰Mg
13	²⁵Al
14	²⁶Si
15	²⁷P
16	²⁸S
17	²⁹Cl
18	³⁰Ar