Radioactivity is the spontaneous disintegration of atomic nuclei to reach stability, which involves the emission of ionizing radiation or particles. This process is known as radioactive decay, nuclear decay, or radioactive disintegration. Radionuclides, which are atoms that undergo this process, can be naturally occurring or artificially produced in particle accelerators or nuclear reactors. The half-life of a radioisotope is the amount of time it takes for half of the radioactive atoms in a sample to decay. There are three types of half-lives: physical, biological, and effective.

1. Cline Reeve Venci L. Argallon

2. What is Radioactivity?
The emission of ionizing radiation or
particles caused by the spontaneous
disintegration of atomic nuclei to reach
stability.

3. Wave

4. Radioactive disintegration / Nuclear
decay / Radioactive decay
• is the process by which an unstable atomic
nucleus loses energy (in terms of mass) by
emitting radiation.
• The atoms involved are called
RADIONUCLIDES.

5. Radionuclides can be naturally
occurring or artificially produced by
PARTICLE ACCELERATOR or NUCLEAR
REACTORS.

6. A radionuclide is an atom that has
excess nuclear energy, making it
unstable.

8. Carbon-14 possesses an unstable nucleus which
undergoes radioactive decay. The basis for
carbon dating is carbon 14.

9. Half-life
The half-life of a radioisotope is the time
required for a quantity of radioactivity to
be reduced to one-half of its original value.

10. 3 types of half-life

11. • Physical half-life is defined as the period
of time required to reduce the
radioactivity level of a source to exactly
one half its original value due solely to
radioactive decay.

12. • The biological half-life of
a biological substance is the time it
takes for half to be removed
by biological processes.

13. • Effective half-life time is the time
interval required for the radioactivity of a
certain amount of radioactive substance
distributed in tissues and organs to
decrease to half its original value due to
radioactive decay and biological
elimination.