Physics: Nuclear Physics - Alpha, Beta, and Gamma Radiation

Radioactivity is the process by which an unstable atomic nucleus loses energy by radiation. The three main types are Alpha ($\alpha$), Beta ($\beta$), and Gamma ($\gamma$).

Atomic notation is written as $^{A}_{Z}X$, where $A$ is the mass number (protons + neutrons) and $Z$ is the atomic number (protons).

Alpha particles ($^{4}_{2}\alpha$ or $^{4}_{2}He$) consist of two protons and two neutrons. They are highly ionizing but have low penetration power, being stopped by a sheet of paper.

Beta particles ($^{0}_{-1}\beta$ or $^{0}_{-1}e$) are high-energy electrons emitted when a neutron in the nucleus turns into a proton. They have moderate ionizing and penetration power, being stopped by a few millimeters of aluminum.

Gamma radiation ($^{0}_{0}\gamma$) consists of high-frequency electromagnetic waves. They have very low ionizing power but high penetration power, requiring several centimeters of lead or meters of concrete to be stopped.

During Alpha decay, the mass number decreases by 4 and the atomic number decreases by 2. During Beta decay, the mass number remains the same and the atomic number increases by 1.