Final answer:
Radioactive decay involves the spontaneous emission of particles and/or energy from unstable isotopes, resulting in the transformation into more stable nuclei and often a different element altogether. The four primary types of decay are alpha, beta, gamma, and neutron emission, with the rate of decay varying significantly between different isotopes.
Step-by-step explanation:
Nuclear Decay Processes
Radioactive decay is a spontaneous process where unstable isotopes emit radiation to become more stable nuclei. The processes that cause radioactive decay of an element and result in transmutation to a new element involve the emission of particles and/or energy. There are four primary types of decay emissions:
- Alpha decay: Emission of an alpha particle, which is a helium nucleus.
- Beta decay: Emission of a beta particle, which can be an electron (beta-minus) or a positron (beta-plus).
- Gamma decay: Emission of gamma rays, which are high-energy photons.
- Neutron emission: Ejection of a neutron from the nucleus.
Examples of nuclear reactions include Uranium-238 decaying to form Thorium-234 with the emission of an alpha particle, or Polonium decaying into a lead nucleus. These reactions can be represented using nuclear symbols to describe the changes occurring during the reactions.
It is important to note that the spontaneity of radioactive decay does not correlate to the rate of decay, which varies widely between isotopes. While all decay processes are spontaneous, some isotopes like Technetium-99m decay rapidly, whereas others, like Uranium-238, have decay rates spanning billions of years.