describe how radioactive isotopes decay
Radioactive isotopes decay through a process known as radioactive decay. During this decay, the nucleus of an unstable atom undergoes spontaneous changes and transforms into a more stable configuration. This process releases radioactive particles and/or energy in the form of radiation.
To describe how radioactive isotopes decay, we need to understand three common types of radioactive decay:
1. Alpha Decay: In alpha decay, an unstable atom emits an alpha particle, which consists of two protons and two neutrons. This emission reduces the atomic number of the parent atom by two and its mass number by four. For example, a common example of alpha decay is the decay of uranium-238 into thorium-234 with the release of an alpha particle:
Uranium-238 -> Thorium-234 + Alpha Particle (Helium-4)
2. Beta Decay: In beta decay, an unstable atom undergoes the transformation of a neutron into a proton or a proton into a neutron. This process releases a beta particle, which can be an electron (β-) or a positron (β+). The emission of a beta particle changes the atomic number of the parent atom while leaving the mass number unchanged. For instance, a common example is the decay of carbon-14 into nitrogen-14 with the emission of a beta particle:
Carbon-14 -> Nitrogen-14 + Beta Particle (Electron)
3. Gamma Decay: After undergoing alpha or beta decay, a nucleus may still be in an excited state. To reach a lower energy state, it releases excess energy in the form of gamma radiation. Gamma decay does not change the atomic number or mass number of the parent atom. For example, after alpha or beta decay, the resulting nucleus may release a gamma ray to stabilize itself further.
It's important to note that the decay process of radioactive isotopes is random—meaning one cannot predict exactly when a specific atom will decay. However, scientists can determine the average lifetime of a large number of atoms by measuring the decay rate, which is expressed as the half-life. The half-life is the time it takes for half of the radioactive isotopes in a sample to decay.
By studying the decay of radioactive isotopes, scientists can gain insights into various fields such as geology, archaeology, medicine, and nuclear energy.