Final answer:
The equation 224/90Th → 220/88Rn + 4/2He represents alpha decay, a type of radioactive decay where an alpha particle is emitted, resulting in a new element with a decreased atomic number and mass.
Step-by-step explanation:
The nuclear reaction represented by 224/90Th → 220/88Rn + 4/2He is an example of alpha decay, which is a type of radioactive decay. In this process, an alpha particle, which is identical to a helium-4 nucleus and symbolized by 4/2He, is emitted from the nucleus of an atom. This causes the original atom to lose two protons and two neutrons, thereby transforming into a different element with a lower atomic number.
Using the given nuclear reaction as an example, we start with thorium-224 which undergoes alpha decay to produce radon-220 and an alpha particle (helium-4). To identify the daughter isotope, we follow the conservation of mass and charge. The mass number decreases by 4 (from 224 to 220), and the atomic number decreases by 2 (from 90 to 88), identifying the product as radon.
This process is one of the common ways that unstable elements (radionuclides) transform into more stable forms. It is widely studied in the fields of nuclear physics and chemistry, and has significant implications in areas such as nuclear medicine, radiometric dating, and understanding the behavior of elements in the environment.