Nuclear decay chain,radium series. Diagram of the nuclear decay chain of uranium-238 (U-238) with isotopes (shown by chemical symbols) plotted by mass number (A) against atomic number (Z). Isotopes are colour-coded by their primary decay route (purple,red arrows: alpha decay; blue,blue arrows: beta decay). Decays are rare (dotted lines) or dominant (solid lines). The dominant route (yellow) ends with the stable (green) lead-206 (Pb-206). Other elements in this natural decay chain are: protactinium (Pa),thorium (Th),radium (Ra),radon (Rn),astatine (At),polonium (Po),bismuth (Bi),thallium (Tl),and mercury (Hg) |