Question:

1 2 3 4 222 Rn 86 234Th 214 Pb 234 Tr I 234Th 90 220Ra 88

Last updated: 5/8/2023

1 2 3 4 222 Rn 86 234Th 214 Pb 234 Tr I 234Th 90 220Ra 88

1 2 3 4 222 Rn 86 234Th 214 Pb 234 Tr I 234Th 90 220Ra 88 221 He He e