22-2-nuclear-forces-and-radioactivity_summary

This section focuses on the structure and properties of the nucleus of an atom, as well as radioactivity—the emission of particles or energy from a nucleus. The nucleus is made up of protons and neutrons, collectively called nucleons, which have nearly the same mass. The atomic number (Z) represents the number of protons within a nucleus and determines the elemental quality of each atom. The mass number (A) represents the total number of protons and neutrons within an atom. A nuclide is used to represent various atoms and is written as X Z A, where X is the atomic symbol, Z is the atomic number, and A is the mass number. Radioactive decay refers to the process in which a nucleus alters its structure to regain equilibrium between the strong nuclear force and the electromagnetic force. There are three types of radioactive decay: alpha (α) decay, in which a nucleus ejects two protons and two neutrons; beta ( β) decay, in which a neutron is transformed into a proton and electron or vice versa; and gamma ( γ) decay, in which a nucleus drops from an excited state to the ground state, releasing a high-energy photon. The nuclear equation for an alpha decay process can be shown as X Z A N → Y Z−2 A−4 N + H 2 4 e, for beta decay as X Z A N → Y Z+1 A N−1 +e+v, and for gamma decay as X A → Y A + γ. The mass number and charge are conserved during all three types of decay, and physical conservation takes place as well. Radiation interacts with substances differently based on its charge. Alpha particles, which carry a net charge of +2, have a short range and short penetrating distance in most materials. Beta particles, which carry a net charge of –1, have a larger range and larger penetrating distance. Gamma rays, which carry no charge, can travel much farther. Explanation: Antique books and manuscripts can be damaged by alpha and beta radiation emissions. These radiations can cause chemical reactions in the materials, such as breaking chemical bonds, which can destroy the physical integrity of the artifacts. High-energy gamma rays, on the other hand, can penetrate solid objects and cause damage to the materials beyond their path, such as deterioration of the paper or other materials used in the book's construction. To preserve the integrity of antique books and manuscripts, it is important to protect them from both alpha and beta radiation emissions, as well as from high-energy gamma rays using lead shielding or other protective materials. For the reading certificate, the following key concepts and terms are covered in this section: * The structure of the nucleus, including the presence of protons and neutrons, and the atomic number and mass number * Radioactivity, nuclear decay, and the types of radiation (alpha, beta, and gamma) * The nuclear equation for each type of decay * The conservation of mass number, charge, and physical conservation during nuclear decay * The difference in penetration distance of radiation based on its charge * Methods for detecting radiation, such as Geiger tubes and scintillators.