Half Lives for Radioactive Elements
5730 years
Nitrogen 14
Carbon 14
4.47 billion years
Lead 206
Uranium 238
704 million years
Lead 207
Uranium 235
14 billion years
Lead 208
Thorium 232
48.8 billion yrs
Strontium 87
Rubidium 87
1.25 billion yrs
Argon 40
Potassium 40
Half life
Stable Daughter
Radioactive Parent