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Periodic table
›
helium
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He-3
Helium-3 (He-3)
Identity
Protons
2
Neutrons
1
Mass number
3
Mass
3.016029 ± 0.000060 u
Mass excess
14.931 MeV
Spin
1/2+*
Stability
stable
Natural occurrence
0.000200 %
of helium
Produced by
H-3
All isotopes of helium