Decay series
An unstable nucleus may emit an alpha or beta particle to form another element, or a gamma ray and become less excited nucleus. This daughter product may also be radioactive and so a whole chain of decay products can be formed.
| Isotope |
Half life |
|
Isotope |
Half life |
| Uranium 238 |
4.5x109 years |
|
Lead 214 |
27 mins |
| Thorium 234 |
24 days |
|
Bismuth 214 |
20 mins |
| Protactinium 234 |
1.2 mins |
|
Polonium 214 |
1.6x10-4 s |
| Uranium 234 |
2.5x105 years |
|
Lead 210 |
19 years |
| Thorium 230 |
8.0x104 years |
|
Bismuth 210 |
5.0 days |
| Radium 226 |
1620 years |
|
Polonium 210 |
138 days |
| Radon 222 |
3.8 days |
|
Lead 206 |
stable |
| Polonium 218 |
3.1 mins |
|
|
|
Lead 206 is stable and is therefore the end of the decay chain.
|
l1N1 = l2N2 etc. or lN = a constant
|
Since the half life (t) is proportional to 1/l:
|
In a decay chain: N1/N2 = T1/T2 etc.
|
|
Since N = (m/M)L T1/T2 = N1/N2 = (m1/M1)/(m2/M2) = (m1/m2)x(M2/M1)
|
