Nuclear Changes

8A Radioactive Decay

• Nuclear Change: any change that alters the composition of the nucleus in an atom

Discovering Radioactivity

• X-ray: used for medical imagery, transportation security, and nondestructive inspection

• Radioactive Decay: the naturally occurring, spontaneous change of an unstable isotope to a more stable one by emitting particles or energy or both

• Strong Force: an attractive force that holds protons and neutrons together in a nucleus

• Types of Radioactive Decay

  • Alpha Decay: a nuclear decay that results in the emission of an alpha particle

  • Beta Decay: a nuclear decay that results in the emission of a beta particle

  • Gamma Decay: a nuclear decay that results in the emission of gamma rays

• Half-life: the time in which half the atoms of a radioactive sample will probably decay

8B: Fission and Fusion

• artificial transmutation: a manmade artificial change

• Fission

  • fission: a nuclear reaction in which a large nucleus splits into smaller nuclei

  • chain reaction: a self-sustaining nuclear fission process in which neutrons produced in one fission reaction trigger more fission events

  • critical mass: the smallest mass of fissionable material that can sustain a chain reaction

• fusion: a nuclear reaction in which small nuclei combine to form a more massive nucleus

8C: Nuclear Changes - Benefits and Risks

• Using Radiation

  • radiotracer: a radioactive isotope used in nuclear medicine to study how an isotope moves through or collects in a certain way

• Effects of Radiation

  • ionizing radiation: radiation that is energetic enough to knock electrons out of atoms or molecules; most damaging to living organisms

  • somatic damage: any damage to cells that are not involved in reproduction, thus harming the organism but not any future offspring

  • genetic damage: any damage done to DNA in cells that can affect growth and reproduction of the cells; can be passed to offspring if it occurs in reproductive cells

• Detecting Radiation

  • Geiger counter: a device designed to measure ionizing radiation

  • dosimeter: a device used to measure exposure to radiation