It's Elemental
Isotopes of the Element Helium
Helium
Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information.
Isotopes With A Known Natural Abundance
| Mass Number | Natural Abundance | Half-life |
| 3 | 0.000134% | STABLE |
| 4 | 99.999866% | STABLE |
Known Isotopes
| Mass Number | Half-life | Decay Mode | Branching Percentage |
| 3 | STABLE | - | - |
| 4 | STABLE | - | - |
| 5 | 7.595×10-22 seconds | Neutron Emission | 100.00% |
| Alpha Decay | 100.00% | ||
| 6 | 801 milliseconds | Beta-minus Decay | 100.00% |
| 7 | 3.038×10-21 seconds | Neutron Emission | No Data Available |
| 8 | 119.1 milliseconds | Beta-minus Decay | 100.00% |
| Beta-minus Decay with delayed Neutron Emission | 16.00% | ||
| 9 | No Data Available | Neutron Emission | 100.00% |
| 10 | 1.519×10-21 seconds | Neutron Emission | 100.00% |
Citation and linking information
For questions about this page, please contact Carol McKisson.