| 1 | Alpha particles α-particles |
Helium nucleus Stopped by paper Highest ionization potential |
|
| 2 | Beta-particles β-particles |
Fast moving electrons Stopped by aluminum Less ionization potential |
|
| 3 | Gamma-particles γ-rays |
Electromagnetic radiation Only stopped by thick a sheet of lead Least ionization potential |
|
| 4 | Half-life | Time in which the activity or mass becomes half | |
| 5 | Atomic symbol |  |
A is the total no of protons and neutrons Z is the total no of protons |
| 6 | Isotopes | Same number of protons but different number of neutrons |
