Helium-10

Properties and data of the isotope ¹⁰He.

Contents

Helium-10 is a radioisotope of the chemical element Helium, which, in addition to the element-specific 2 protons, has 8 neutrons in the atomic nucleus, resulting in the mass number 10. The very short-lived, unstable and therefore radioactive nuclide, which can only be produced artificially, has no practical significance; The study of ¹⁰He serves exclusively academic purposes.

He-10 is the heaviest known and the shortest-lived He isotope with a half-life of about 2.7 zeptoseconds.

See also: List of individual Helium isotopes (and general data sources).

General data

Name of the isotope:Helium-10; He-10Symbol:¹⁰He or 102HeMass number A:10 (= number of nucleons)Atomic number Z:2 (= number of protons)Neutrons N:8Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):4 (= neutron-proton ratio)Neutron excess (N-Z):6Isotopic mass:10.05282(10) u (atomic weight of Helium-10)Nuclide mass:10.0517228 u (calculated nuclear mass without electrons)Mass excess:49.20151 MeVMass defect:0.032149392000001 u (per nucleus)Nuclear binding energy:29.94696575 MeV (per nucleus)
2.99469658 MeV (average binding energy per nucleon)Half-life:2.68882 zsDecay constant λ:2.577886138008 × 10⁺²⁰ s^-1Specific activity α:1.552439344396 × 10⁺⁴³ Bq g^-1
4.195782011882 × 10⁺³² Ci g^-1Spin and parity:
(nuclear angular momentum)(0+)Isobaric spin: 3Year of discovery:1994

Radioactive Decay

Half-life T_½ = 2.68882 zs respectively 2.68882 × 10^-21 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
n	⁹He	100 %	15.759(71) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 8) and isobaric (same nucleon number A = 10) with Helium-10. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.