<Tr> <Td> O </Td> <Td> 8 </Td> <Td> 13 </Td> <Td> 21.008656 (13) </Td> <Td> 3.42 (10) s </Td> <Td> β </Td> <Td> </Td> <Td> (1 / 2, 3 / 2, 5 / 2) + </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> O </Td> <Td> 8 </Td> <Td> 14 </Td> <Td> 22.00997 (6) </Td> <Td> 2.25 (15) s </Td> <Td> β (78.0%) </Td> <Td> </Td> <Td> 0 + </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> β, n (22.0%) </Td> <Td> </Td> </Tr> <Tr> <Td> O </Td> <Td> 8 </Td> <Td> 15 </Td> <Td> 23.01569 (13) </Td> <Td> 82 (37) ms </Td> <Td> β, n (57.99%) </Td> <Td> </Td> <Td> 1 / 2 + #</Td> <Td> </Td> <Td> </Td> </Tr>

The atomic mass of oxygen is 16. how many neutrons does oxygen have in its nucleus