# Inner electrons 49 # Outer electrons 38 # Protons 87 Abundance 7.00 An-Isotope 38: 87 Approval Stats BE - Actual 757.36 BE - Nucleon 8705.24 Element Strontium Half Life Stable Mass Actual 86.91 Mass Calculated 87.68 Mass H Norm 86.23 Stability Stable