Question

What particle is produced during the following decay processes: (a) sodium-24 decays to magnesium-24; (b) mercury-188 decays to gold-188; (c) iodine-122 decays to xenon-122; (d) plutonium-242 decays to uranium-238?

Short answer

(a) Sodium-24 decays to magnesium-24 through beta decay, producing a beta particle (electron). (b) Mercury-188 decays to gold-188 through beta-plus decay, producing a positron. (c) Iodine-122 decays to xenon-122 through beta decay, producing a beta particle (electron). (d) Plutonium-242 decays to uranium-238 through alpha decay, producing an alpha particle (helium-4 nucleus).

Step-by-step solution

Identify the decay type and particle produced

In this case, the atomic number of sodium increases by one as it decays to magnesium, which indicates a beta decay. A neutron is converted into a proton, and a beta particle (electron) is emitted. Thus, the particle produced is a beta particle (electron). #a. Mercury-188 decays to gold-188#

Identify the decay type and particle produced

Mercury's atomic number decreases by one as it decays to gold, which indicates a beta-plus decay. A proton is converted into a neutron, and a positron (anti-electron) is emitted. Thus, the particle produced is a positron. #c. Iodine-122 decays to xenon-122#

Identify the decay type and particle produced

In this case, the atomic number of iodine increases by one as it decays to xenon, which indicates a beta decay. A neutron is converted into a proton, and a beta particle (electron) is emitted. Thus, the particle produced is a beta particle (electron). #d. Plutonium-242 decays to uranium-238#

Identify the decay type and particle produced

In this case, the atomic number of plutonium decreases by two as it decays to uranium, which indicates an alpha decay. The nucleus loses 2 protons and 2 neutrons (a helium-4 nucleus). Thus, the particle produced is an alpha particle (helium-4 nucleus).

Key concepts

Beta Decay

Beta decay is a fascinating process where an atom's nucleus changes, leading to the emission of a beta particle. This transformation occurs because a neutron inside the nucleus converts into a proton. When this happens, the atom's atomic number, which you can think of as its unique identifier, increases by one.
It is important to note that there are two kinds of beta decay. The first is typical beta decay, or beta minus decay, where a negatively charged electron is emitted. In this process, neutrons become protons, leading to the expulsion of an electron (the beta particle). This is what occurred when sodium-24 decayed into magnesium-24, as discussed in the exercise.
Beta decay is crucial to understanding nuclear energy and keeps the balance in nature, influencing elements' life cycles in the universe.

Alpha Decay

Alpha decay is another type of nuclear decay that plays a crucial role in nuclear chemistry. In this process, a heavy atom's nucleus releases an alpha particle. This alpha particle comprises two protons and two neutrons, which is equivalent to a helium-4 nucleus.
When a nucleus undergoes alpha decay, it loses a significant portion of its atomic weight, decreasing the atomic number by two and the mass number by four. This was exemplified in the decay of plutonium-242 to uranium-238 in the exercise. The energy released in this decay is usually in the form of high kinetic energy, making alpha particles important in radiation therapy and other applications.
Understanding alpha decay helps us better grasp how radioactive materials transform over time and their behavior in environments such as nuclear reactors.

Positron Emission

Positron emission, also known as beta-plus decay, is an intriguing nuclear decay process where a proton within a nucleus is transformed into a neutron. During this transformation, a positron is emitted. A positron is the antimatter counterpart of an electron, possessing a positive charge instead of a negative one.
In the case of mercury-188 decaying into gold-188, the atomic number of mercury decreases by one as it transforms into gold through positron emission.
This decay process is not only essential in nuclear physics but also holds significance in medical imaging techniques like Positron Emission Tomography (PET) scans. By understanding this, scientists can visualize biological processes happening in real-time within the human body.

Radioactive Particles

Radioactive particles are the building blocks of nuclear decay, and understanding them is key to grasping how radioactivity affects our world. Every particle has its characteristics and impacts different nuclear processes.

• Alpha particles (comprised of two protons and two neutrons) are relatively heavy and carry a positive charge. They are emitted in alpha decay and can travel only a short distance through the air.
• Beta particles are lighter electrons emitted in beta decay. They have a greater penetration ability compared to alpha particles but are still stopped by materials like aluminum foil.
• Positrons, the positive counterparts of electrons, are released during positron emission. They quickly collide with electrons, resulting in their annihilation and conversion into energy.

Understanding these particles allows us to have a deeper insight into nuclear reactions and their applications, ranging from energy production to our understanding of atomic structures.