Alpha (α) decay

Definition

Alpha (α) decay is a type of radioactive decay where an unstable nucleus emits an alpha particle, consisting of 2 protons and 2 neutrons. This process reduces the atomic number by 2 and the mass number by 4.

5 Must Know Facts For Your Next Test

1. Alpha particles are helium nuclei composed of 2 protons and 2 neutrons.
2. In alpha decay, the parent nucleus loses an alpha particle, resulting in a daughter nucleus with an atomic number decreased by 2 and a mass number decreased by 4.
3. Alpha particles have relatively low penetration power and can be stopped by a sheet of paper or human skin.
4. Common examples of alpha emitters include radium-226 ($^{226}_{88}Ra$) decaying to radon-222 ($^{222}_{86}Rn$).
5. Alpha decay is typically observed in heavy elements with atomic numbers greater than 82.

Review Questions

Related terms

Beta (β) Decay: A type of radioactive decay where a neutron is converted into a proton, emitting a beta particle (electron) and an antineutrino.

Gamma (γ) Decay: A type of radioactive decay where an excited nucleus releases energy in the form of gamma rays without changing its atomic or mass numbers.

Half-life:

The time required for half the atoms in a sample of a radioactive substance to undergo decay.