Nuclear Radiation and Ions

Nuclear Particles and Radiation

  • Alpha Particle

    • Symbol: ( \alpha )

    • Composition: 2 protons and 2 neutrons (helium nucleus)

    • Charge: +2

    • Mass: approximately 4 atomic mass units (amu)

  • Beta Particle

    • Symbol: ( \beta )

    • Type: High-energy, high-speed electron or positron emitted by certain types of radioactive nuclei.

    • Charge: -1 (electron) or +1 (positron)

    • Mass: approximately 1/1836 amu

  • Gamma Ray

    • Symbol: ( \gamma )

    • Type: Electromagnetic radiation of high frequency

    • Charge: Neutral

    • Mass: No mass (pure energy)

Nuclear Equations

  • Example nuclear equation:

    • Write in the form: ( 81Rb \rightarrow 0 + -1 \beta + 81Sr )

  • Balancing nuclear equations requires ensuring that the number of protons and the total mass remains constant on both sides of the equation.

Radioactive Particles and Their Properties

  • Lowest Penetrating Power:

    • Answer: a. Alpha particle (least penetrating, stopped by paper or skin)

    • Beta particles are more penetrating but stopped by aluminum; gamma rays have the highest penetrating power, needing thick lead or several centimeters of concrete to be blocked.

The Periodic Table

  • Representative Elements (Group Markings):

    • Groups are marked as 1A to 8A, reflecting their similar properties, including metals, semimetals, and nonmetals.

    • Group 1A: Alkali metals (e.g., Lithium: ( Li = 6.941 ), Sodium: ( Na = 22.98977 ))

    • Group 2A: Alkaline earth metals (e.g., Magnesium: ( Mg = 24.3050 ))

    • Groups 3A to 8A list the different families of elements, including noble gases (Group 8A).

  • Transition Metals:

    • Groups 3B to 8B, generally known for their d-orbitals, and their unique properties in catalysis and complex formation.

  • Lanthanide and Actinide Elements:

    • Enclosed sections for elements with less common properties and larger atomic numbers indicating their f-orbital configuration.

Nuclear Reactions and Half-Life

  • Half-Life Definition:

    • The time required for one-half of the nuclei in a sample to decay.

    • Example: The half-life of Carbon-14, (^{14}C), is ( 5730 ) years.

  • Importance of Knowing Half-Life:

    • In medicine: To limit patient exposure to radiation, opting for isotopes with shorter half-lives enables rapid decay and limits long-term radioactivity.

    • In understanding nuclear disasters, such as Chernobyl or Fukushima, half-lives of emitted isotopes inform health and safety decisions.

Applications of Radioisotopes in Medicine

  • Different isotopes have specific applications based on their properties:

    • (^{24}Na): Used for detecting blood vessel obstruction.

    • (^{75}Se): Used in imaging the spleen and diagnosing gastrointestinal disorders.

    • (^{137}Cs): Commonly used in radiation therapy for cancer treatment.

Types of Radiation Therapy

  • External Therapy:

    • Utilizes gamma rays ((\gamma) rays) from cobalt-60 directed at the tumor.

    • Risk of radiation sickness due to effect on healthy tissue.

  • Internal Therapy:

    • Example: Iodine-131 treatment for thyroid conditions.

    • Administered in larger doses than diagnostic purposes. The iodine accumulates in the thyroid, allowing for targeted cancer treatment.

Ion Formation

  • Ions:

    • Formed when atoms gain or lose electrons, resulting in a net charge.

    • Cations: Positively charged ions formed by loss of electrons (e.g., ( Li^+ ), ( Na^+ )).

    • Anions: Negatively charged ions resulting from gain of electrons (e.g., oxide ion ( O^{2-} )).

  • Examples of Monoatomic Ions:

    • Lithium: (\text{Li} \rightarrow \text{Li}^+ )

    • Iron: ( \text{Fe}^{2+} ) (Iron(II) ion), ( \text{Fe}^{3+} ) (Iron(III) ion).

Naming Ions

  • Naming Conventions:

    • Use of Roman numerals to indicate charge of transition metals (e.g., Iron II = Fe(^{2+}), Iron III = Fe(^{3+})).

    • Common names for ions may include endings like -ous or -ic for different oxidation states (e.g., Chromium(III) as "chromic ion").

  • Examples of Ions:

    • ( ext{Cr}^{2+} ): Chromium(II) ion, Chromous ion.

    • ( ext{Cu}^+ ): Copper(I) ion, Cuprous ion.

    • ( ext{O}^{2-} ): Oxide ion, an example of an anion.