The transmutation of a radioactive uranium isotope, 234/92u , into a radon isotope, 222/86rn , involves a series of three nuclear reactions. at the end of the first reaction, a thorium isotope,230/90th , is formed and at the end of the second reaction, a radium isotope, 226/88ra , is formed. in both the reactions, an alpha particle is emitted. write the balanced equations for the three successive nuclear reactions.