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Rapid Review
Types of Radioactive Decay
Mode of decay |
Effect on parent nucleus |
Example |
a emission |
Mass number decreases by 4 Atomic number decreases by 2 |
86 Rn210 ® 84Po206 + 2He4 |
b emission |
Neutron turns into a proton Atomic number increases by 1 Mass number remains the same |
6 C14 ® 7N14 + -1e0 |
Electron capture |
Proton turns into a neutron Atomic number decreases by 1 Mass number remains the same |
53 I125 + -1e0 ® 52Te125 + X-ray photon(The captured electron decelerates and its kinetic energy is converted into electromagnetic energy) |
Positron emission |
Proton turns into a neutron Atomic number decreases by 1 Mass number remains the same |
5 B8 ® 4Be8 + +1e0 |
g emission | None except nucleus becomes less excited |
43 Tc99M ® 43Tc99 + g(The "M" stands for metastable) |
Spontaneous fission | Becomes much smaller |
98 Cf252 ® 54Xe140 + 44Ru108 + 4 0n1 |