<Tr> <Td> Th </Td> <Td> </Td> <Td> U </Td> <Td> U </Td> <Th> 0.7 G--14.1 G </Th> </Tr> <Tr> <Td_colspan="9"> <P> Legend for superscript symbols ₡ has thermal neutron capture cross section in the range of 8--50 barns ƒ fissile m metastable isomer No primarily a naturally occurring radioactive material (NORM) þ neutron poison (thermal neutron capture cross section greater than 3k barns) † range 4--97 y: Medium - lived fission product ‡ over 200,000 y: Long - lived fission product </P> </Td> </Tr> <P> Legend for superscript symbols ₡ has thermal neutron capture cross section in the range of 8--50 barns ƒ fissile m metastable isomer No primarily a naturally occurring radioactive material (NORM) þ neutron poison (thermal neutron capture cross section greater than 3k barns) † range 4--97 y: Medium - lived fission product ‡ over 200,000 y: Long - lived fission product </P> <Table> <Tr> <Td_colspan="16"> Region of relative stability: radium - 226 to einsteinium - 252 </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> 88 </Td> <Td> 89 </Td> <Td> 90 </Td> <Td> 91 </Td> <Td> 92 </Td> <Td> 93 </Td> <Td> 94 </Td> <Td> 95 </Td> <Td> 96 </Td> <Td> 97 </Td> <Td> 98 </Td> <Td> 99 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> 154 </Td> <Td> </Td> <Td_colspan="3"> <Table> <Tr> <Td_colspan="3"> Half - life Key </Td> </Tr> <Tr> <Td> 1 </Td> <Td> 10 </Td> <Td> 100 </Td> </Tr> <Tr> <Td> 1k </Td> <Td> 10k </Td> <Td> 100k </Td> </Tr> <Tr> <Td> 1M </Td> <Td> 10M </Td> <Td> 100M </Td> </Tr> <Tr> <Td> 1G </Td> <Td> 10G </Td> <Td> (a) </Td> </Tr> </Table> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Cm </Td> <Td> </Td> <Td> Cf </Td> <Td> </Td> <Td> </Td> <Td> 154 </Td> </Tr> <Tr> <Td> 153 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Cf </Td> <Td> Es </Td> <Td> </Td> <Td> 153 </Td> </Tr> <Tr> <Td> 152 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Cm </Td> <Td> </Td> <Td> Cf </Td> <Td> </Td> <Td> </Td> <Td> 152 </Td> </Tr> <Tr> <Td> 151 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Cm </Td> <Td> Bk </Td> <Td> Cf </Td> <Td> </Td> <Td> </Td> <Td> 151 </Td> </Tr> <Tr> <Td> 150 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Pu </Td> <Td> </Td> <Td> Cm </Td> <Td> Bk </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 150 </Td> </Tr> <Tr> <Td> 149 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Cm </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 149 </Td> </Tr> <Tr> <Td> 148 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Pu </Td> <Td> Am </Td> <Td> Cm </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 148 </Td> </Tr> <Tr> <Td> 147 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Pu </Td> <Td> ⁂ </Td> <Td> Cm </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 147 </Td> </Tr> <Tr> <Td> 146 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> U </Td> <Td> </Td> <Td> Pu </Td> <Td> Am </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 146 </Td> </Tr> <Tr> <Td> 145 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Pu </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 145 </Td> </Tr> <Tr> <Td> 144 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> U </Td> <Td> Np </Td> <Td> Pu </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 144 </Td> </Tr> <Tr> <Td> 143 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> U </Td> <Td> Np </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 143 </Td> </Tr> <Tr> <Td> 142 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Th </Td> <Td> </Td> <Td> U </Td> <Td> Np </Td> <Td> Pu </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 142 </Td> </Tr> <Tr> <Td> 141 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> U </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 141 </Td> </Tr> <Tr> <Td> 140 </Td> <Td> </Td> <Td> Ra </Td> <Td> </Td> <Td> Th </Td> <Td> Pa </Td> <Td> U </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td_colspan="3"> <Table> <Tr> <Td_colspan="2"> Table Axes </Td> </Tr> <Tr> <Td> Neutrons </Td> <Td> (N) </Td> </Tr> <Tr> <Td> Protons </Td> <Td> (Z) </Td> </Tr> </Table> </Td> <Td> </Td> <Td> 140 </Td> </Tr> <Tr> <Td> 139 </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> Th </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 139 </Td> </Tr> <Tr> <Td> 138 </Td> <Td> </Td> <Td> Ra </Td> <Td> Ac </Td> <Td> Th </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> 138 </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> 88 </Td> <Td> 89 </Td> <Td> 90 </Td> <Td> 91 </Td> <Td> 92 </Td> <Td> 93 </Td> <Td> 94 </Td> <Td> 95 </Td> <Td> 96 </Td> <Td> 97 </Td> <Td> 98 </Td> <Td> 99 </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td_colspan="16"> Only nuclides with a half - life of at least one year are shown on this table . </Td> </Tr> </Table>

Where are the most massive elements on the periodic table