Half-life (element)

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This article is about the property of radioactive elements. For the video game, see Half-Life (video game).
Number of
half-lives
that have happened
Parts
remaining
As
power
of 2
0 1/1 1 / 20
1 1/2 1 / 21
2 1/4 1 / 22
3 1/8 1 / 23
4 1/16 1 / 24
5 1/32 1 / 25
6 1/64 1 / 26
7 1/128 1 / 27
... ...
N 1 / 2N 1 / 2N

The half-life of a radioactive element is the time it takes for half the radioactive atoms to decay. Using a Geiger-Muller detector, the half-life is how long it takes to half the original count rate.

Radioactive atoms have unstable nuclei. Their nuclei are unstable because the arrangement of protons and neutrons in them are unsteady, making them shake until that they begin to decay and change into completely different types of atoms by releasing certain types of radioactive particles, such as alpha particles, beta particles or gamma rays. This is known as radioactive decay. For example, a radioactive carbon-14 atom releases a beta particle to become nitrogen-14.

Radioactive elements have all sorts of different half-lives, varying from less than a second to thousands of years. For example, carbon-14 has a half-life of 5715 years. This means that after 5715 years half the amount of radioactive carbon-14 atoms haved decayed and turned into nitrogen-14 atoms.

As an Example, U232 has a half-life of about 69 years. Pu238 has a half-life of 88 years. C14, which is used to find the age of fossils, has a half-life of 5730 years.