Nuclear Chemistry

Chemistry Inside the Atom

What is the half-life of a radioactive species?

The half-life of a radioactive species is the amount of time it takes the quantity of the species to decrease by half. After one half-life, ½ of the initial quantity of material will remain, after two ¼ will remain, after three 1/8 will remain, and so on. Half-lives of radioactive nuclei vary widely, and we’ll list just a few values below to give an idea of the range of timescales covered.

Radioactive Nucleus Half-Life
Carbon-14 5,730 years
Lead-210 22.3 years
Mercury-203 46.6 days
Lead-214 26.8 minutes
Nitrogen-16 7.13 seconds
Polonium-213 0.000305 seconds


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