<page_title> Isotopes of fermium </page_title> <section_title> List of isotopes </section_title> <table> <cell> 241Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 242Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 243Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 244Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 245Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 246Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 247Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 248Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 249Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 250Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 251Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 252Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 253Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 254Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 255Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 256Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 257Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 258Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 259Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 260Fm <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> </table>
There are 20 known isotopes ranging in atomic mass from ²⁴¹Fm to ²⁶⁰Fm.