Physics Chapter on Radiation and Atoms

Mendeleev arranged elements based on their atomic weight, while Bohr proposed a model with a central positively charged nucleus surrounded by negatively charged electrons orbiting it.

The number of protons in an atom's nucleus determines the atomic number (Z).

Atoms of the same element with the same number of protons but different numbers of neutrons. They have the same atomic number but different mass numbers.

The term 'nuclide' can also refer to isotopes of an element.

Radiation is the propagation of energy through space or matter. It can be natural (e.g., cosmic rays, earth sources) or man-made (e.g., nuclear reactors, radioactive materials).

Radiation protection is crucial because ionizing radiation can interact with matter (human tissue), causing biological changes.

X-ray interactions with matter can lead to biological changes. Understanding how radiation interacts with cells is essential for technologists to protect themselves and patients.

The basic building blocks of an atom include protons (positive charge), neutrons (no charge), and electrons (negative charge).

A positively charged particle emitted from the nucleus of an atom during radioactive decay. It consists of two protons and two neutrons, essentially a Helium nucleus.

A high-speed electron emitted from the nucleus of an atom during radioactive decay. It can be either negatively charged (electron) or positively charged (positron).

A type of electromagnetic radiation that travels at the speed of light. They have no mass and carry high energy.

A neutral particle found in the nucleus of an atom. It has no electrical charge and can interact with the nucleus of other atoms.

A type of electromagnetic radiation that travels at the speed of light. They typically have lower energy than gamma rays and are often used in medical imaging.

The process by which an unstable nucleus releases energy in the form of radiation. This can involve emitting particles like alpha or beta particles, or electromagnetic radiation like gamma rays.

The number of ion pairs formed per unit energy by a type of radiation. Higher specific ionization means the radiation is more likely to cause damage to biological tissue.

The distance a type of radiation can travel through a medium before it loses all its energy. Alpha particles have a short range due to heavy weight, while beta particles have a longer range.

Neutrons are subatomic particles found in the nucleus of an atom. They have no electrical charge and a mass slightly greater than protons. They are crucial for holding the nucleus together via the strong force, which binds protons and neutrons.

X-rays and gamma rays are forms of electromagnetic radiation. They are high-energy photons that can ionize matter. While they differ in their origin (X-rays are produced extranuclearly, gamma rays intranuclearly), both are highly penetrating and pose potential external hazards.

Photoelectric effect, Compton scattering, and pair production are three major ways X-ray photons interact with matter. These interactions occur at the atomic level and have different consequences for energy transfer and the path of the photon.

Wave-particle duality describes the nature of light and other electromagnetic radiation. Depending on the experiment, it can exhibit both wave-like and particle-like properties. This means light acts as a wave when propagating (interference) and as a particle when interacting with matter (photoelectric effect).

The photoelectric effect occurs when an X-ray photon interacts with an atom, completely transferring its energy to an electron, ejecting the electron from the atom. This results in the absorption of the X-ray photon.