ocr: Current Series: Actinium Series Leam Uranium: 235 Current Isotope: Actinium-227 Proton no. 89 Nucleon no. 227 Thorium 231 Investigate Protactinium 231 Emission Type u Actinium 227 a Alpha Francium 223 P Beta Radium 223 Y Gamma Radon 219 Backtrack