<Tr> <Td> 96 </Td> <Td> curium </Td> <Td> 7014492298560000000 ♠ 1.56 × 10 a </Td> <Td> Cm </Td> </Tr> <Tr> <Td> 43 </Td> <Td> technetium </Td> <Td> 7014132541920000000 ♠ 4.2 × 10 a </Td> <Td> Tc </Td> </Tr> <Tr> <Td> 93 </Td> <Td> neptunium </Td> <Td> 7013676594944000000 ♠ 2.144 × 10 a </Td> <Td> Np </Td> </Tr> <Tr> <Td> 91 </Td> <Td> protactinium </Td> <Td> 32,760 a </Td> <Td> Pa </Td> </Tr>

Which is the most stable element in the periodic table