Answer: Radium-226 which has a half life of 1600 years yields an alpha particle and Radon-222. Radon-222 which has a half life of 3.82 days yields an alpha particle and Polonium-228. Polonium-228 has a half life of 3.05 minutes yields an alpha particle and Lead-214. This Lead-214 has a half life of 26.8 minutes yields a beta particle and Bismuth-214. Bismuth-214 has a half life of 19.7 minutes yields a beta particle and Polonium-214. Polonium-214 has a half life of 0.16 millisecond yields and alpha particle and Lead-210. Lead-210 has a half life of 22 years yields a beta particle and Bismuth-210. Bismuth-210 has a 5 day half life yields a beta particle and Polonium-210. Polonium-210 has a half life of 138 days yields an alpha particle and Lead-206. This Lead-206 is stable.