Isotopes of Helium (He)

Symbol Mass Number Relative Atomic Mass Isotopic Composition
3He 3 3.0160293191(26) 0.00000134(3)
4He 4 4.00260325415(6) 0.99999866(3)
5He 5 5.012220(50)
6He 6 6.0188891(8)
7He 7 7.028021(18)
8He 8 8.033922(7)
9He 9 9.043950(30)
10He 10 10.052400(80)

Legend

Mass Number
Relative Atomic Mass
Isotopic Composition
Standard Atomic Weight
He: 4.002602(2)
Notes (He)

Isotopic Composition