Question

223Ra decays by alpha emission with a half-life of 11.43 days. For a 1.0g sample of 223Ra, after one half-life, what mass of 223Ra remains? What has happened to the remaining mass?

Answer 1

₈₈ Ra²²³ ---------------------------> ₈₆Rn²¹⁹ + ₂He⁴

initial 1.0 g

after one half-life remaining mass = 0.5 g

remaining mass is converted into ₈₆Rn²¹⁹ nuclide.