Recording-2025-02-20T17:00:09.111Z

Basic Concepts of Atomic Structures

• Atomic Structure: The nucleus is the central part of an atom containing protons and neutrons. The number of protons is equal to the number of electrons, which determines the atomic number and identity of the element.

• Protons: Positively charged particles found in the nucleus. Their number defines the atomic number of an element.

• Neutrons: Neutral particles also found in the nucleus, contributing to the atomic mass but not affecting the charge.

• Electrons: Negatively charged particles that orbit the nucleus. They have very little mass compared to protons and neutrons.

Electron Shells and Energy Levels

• Electron Shells: Electrons are arranged in layers, with a maximum of seven shells denoted by K, L, M, N, O, P, and Q from the innermost to the outermost shell.

• Energy Levels: The shells represent different energy levels; K is closest to the nucleus and has the highest energy, while Q is the farthest and has the lowest.

Quantum Mechanical Model

• Quantum Mechanical Model: This model describes the behaviors of electrons in three-dimensional space and their likelihood of being located in certain regions around the nucleus, forming bonds.

• Types of Bonds: Electrons can be shared (covalent bonds, typically between nonmetals like water) or transferred (ionic bonds, typically between metals).

States of Matter

• Matter: Anything that has mass and occupies space. It exists in various states:

  • Solid: Tightly packed particles; retains shape.

  • Liquid: Less tightly packed particles; can flow and take the shape of the container.

  • Gas: Particles are far apart and move freely; has no fixed shape or volume.

  • Plasma: A gaseous state formed when gases are heated to high temperatures, resulting in ionized particles.

Radiation and Radioactivity

• Radiation: The emission of energy through space in wave or particle form, which can lead to ionization, the process where atoms gain or lose electrons, forming ions.

  • Ionizing Radiation: Capable of removing electrons from atoms, includes X-rays and gamma rays.

  • Particle vs. Electromagnetic Radiation: Particle radiation includes particles like alpha and beta particles, while electromagnetic radiation includes waves such as UV light and microwaves.

  • Alpha Particles: Positively charged, large in comparison, and with low penetration power.

  • Gamma Rays: High energy, no mass, and deep penetration.

  • X-rays: Similar to gamma rays but with slightly lower energy, useful in medical imaging.

X-ray Production and Functionality

• X-ray Machine Components: Key parts include the control panel, tube head (filled with oil for cooling), tube head seal, collimator (restricts beam size), and glass housing.

  • Anode and Cathode: The flow of electrons from the cathode to the anode produces X-radiation when electrons collide with a metal target.

  • Radiation: Energy carried by waves or streams of particles, essential in medical imaging (radiology).

  • Radiographs: Images produced on receptors by exposure to ionizing radiation, essential for diagnosing dental and medical conditions.

  • Image Receptors: Recording mediums like X-ray films or digital sensors used to capture images.

X-ray Image Quality Factors

• Exposure Factors: Voltage, milliampere settings, and exposure time can affect the density and contrast of radiographs.

  • Contrast: Differentiation of shades of gray in an image, influenced by voltage levels.

  • Beam Intensity: Determined by the distance from the source, exposure time, and energy of the X-ray beam.

Radiation Effects and Safety

• Ionizing Radiation Effects: Divided into stochastic (random effects) and deterministic (direct effects based on dose). Critical organs affected include the thyroid, bone marrow, skin, and eyes.

• Radiation Measurement:

  • Units of Measurement: Grays (Gy) measure absorbed radiation dose, assessing risk and biological effects associated with exposure to radiation.