Column Descriptions Relative Isotopic Standard Isotope Atomic Mass Composition Atomic Weight Notes _________________________________________________________________________ 31 Ga 69 68.9255735(13) 0.60108(9) 69.723(1) 71 70.92470258(87) 0.39892(9) _________________________________________________________________________NIST | Physical Measurement Laboratory | Physical Reference Data | Atomic Weights and Isotopic Compositions Main Page