Explain the process of radioactive decay. What happens during radioactive decay, and what is the result at the end of radioactive decay?

Answer 1

Radioactive decay is a natural process by which an unstable atomic nucleus loses energy by emitting radiation. This process leads to the transformation of the nucleus into a more stable configuration, which can involve a change in the number of protons and/or neutrons. The primary types of radioactive decay include alpha decay, beta decay, and gamma decay.

Types of Radioactive Decay:

1. Alpha Decay:

   • In alpha decay, an atomic nucleus releases an alpha particle, which consists of 2 protons and 2 neutrons (essentially a helium nucleus). This results in a decrease in the atomic number by 2 and the mass number by 4, producing a new element.
   • Example: Uranium-238 decays into Thorium-234 by emitting an alpha particle.

2. Beta Decay:

   • In beta decay, a neutron in the nucleus transforms into a proton and emits a beta particle (an electron or a positron). This process increases the atomic number by 1 (in the case of beta minus decay) or decreases it by 1 (in the case of beta plus decay), while the mass number remains unchanged.
   • Example: Carbon-14 decays into Nitrogen-14 through beta minus decay.

3. Gamma Decay:

   • Gamma decay occurs when an excited nucleus releases energy in the form of gamma radiation (high-energy photons) without changing the number of protons or neutrons. This process usually follows alpha or beta decay as the nucleus moves to a lower energy state.
   • Example: After undergoing alpha decay, a nucleus may emit gamma rays to shed excess energy.

The Process of Radioactive Decay:

1. Instability of Nucleus: The nucleus of a radioactive atom is unstable due to an imbalance in the number of protons and neutrons, which can create an excess of energy or mass.
2. Emission of Particles or Radiation: To achieve stability, the nucleus emits an alpha particle, a beta particle, or gamma radiation, reducing its energy and moving towards a more stable state.
3. Transformation: The emission results in a change of the atomic structure, forming a new element or isotope. The new nucleus may still be unstable and can undergo further decay processes.
4. Continued Decay: This process continues over time, often resulting in a series of decay events, known as a decay chain, until a stable, non-radioactive isotope is formed.

Result at the End of Radioactive Decay:

Eventually, after a series of decay events, the radioactive material will transform into a stable isotope, ceasing to emit radiation. The time taken for half of the original quantity of a radioactive substance to decay is called its half-life, which can range from fractions of a second to billions of years, depending on the isotope. When the decay process is complete, the original radioactive element has been transformed entirely into stable products, often consisting of non-radioactive elements.

In summary, radioactive decay is a fundamental process in nuclear physics, leading to the transformation of unstable isotopes into stable ones, accompanied by the emission of radiation.