He
Helium
Z = 2 · Noble Gas · 4.003 u
Basic properties
- Atomic number (Z)
- 2
- Standard atomic mass
- 4.003 u
- Category
- Noble Gas
Isotopes & cross-section data
| Isotope | Mass (A) | Half-life | ZAID | Libraries |
|---|---|---|---|---|
| He-3 | 3 | Stable | 2003 | .80c.71c.70c |
| He-4 | 4 | Stable | 2004 | .80c.71c.70c |