Alpha Decay

Definition and Process

Alpha (α) decay is a type of radioactive decay in which an unstable atomic nucleus emits an alpha particle, resulting in the transformation of the original atom into a new element. An alpha particle consists of 2 protons and 2 neutrons, making it identical to a helium-4 nucleus.

• Alpha Particle Representation: or

• General Equation: When an atom undergoes alpha decay, its atomic number decreases by 2 and its mass number decreases by 4.

Example:

• Polonium-210 () undergoes alpha decay:

Properties of Alpha Particles

• Size: Alpha particles are the largest among common radioactive emissions (alpha, beta, gamma).

• Ionizing Power: They have the highest ionizing power, making them highly damaging to biological tissues if ingested or inhaled.

• Penetrating Power: Alpha particles have the lowest penetrating power and can be stopped by a sheet of paper, clothing, or even the outer layer of human skin.

Balanced Nuclear Equations for Alpha Decay

When writing a balanced nuclear equation for alpha decay, ensure that both the sum of the mass numbers (top numbers) and the sum of the atomic numbers (bottom numbers) are equal on both sides of the equation.

• General Form:

Examples

• Curium-248 ():

• Bismuth-207 ():

Summary Table: Properties of Alpha, Beta, and Gamma Radiation

Additional info: The table above is included to provide context for the properties of alpha particles compared to other common types of radiation, which is a typical topic in GOB Chemistry courses.