Nucleus & Radioactivity: α, β, γ Emissions, Half-Life & Applications

Radioactive Emissions

Radioactive elements emit radiation as they decay. The three main types of radioactive emissions are:

• Alpha (α) Particles: Consist of 2 protons and 2 neutrons, identical to a helium nucleus. They have a positive charge and are the least penetrating, stopped by paper or skin.
• Beta (β) Particles: High-speed electrons or positrons. They have a negative or positive charge and are more penetrating than alpha particles, stopped by a few millimeters of aluminum.
• Gamma (γ) Rays: Electromagnetic waves with no mass or charge. They are the most penetrating, requiring thick lead or concrete to reduce their intensity.

Understanding Half-Life

The half-life of a radioactive substance is the time it takes for half of the radioactive nuclei in a sample to decay. It is a constant property for each radioactive isotope.

For example, if a substance has a half-life of 5 years, after 5 years, only half of the original amount remains radioactive.

Calculating Half-Life

The formula to calculate the remaining quantity of a substance after a certain number of half-lives is:

$$N = N_0 \left( \frac{1}{2} \right)^n$$

• $N$ = remaining quantity
• $N_0$ = initial quantity
• $n$ = number of half-lives

Applications of Radioactivity

Radioactivity has various applications, including:

• Medical Uses: Radioisotopes are used in medical imaging and cancer treatment (e.g., iodine-131 for thyroid treatment).
• Archaeological Dating: Carbon-14 dating helps determine the age of ancient artifacts and fossils.
• Industrial Uses: Radioactive tracers are used to detect leaks in pipelines and study wear in engines.