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Nuclear Structure and Radioactivity

Nuclear Structure and Radioactivity . Atomic Notation Review. Example:. Element: Radon # protons: 86 # neutrons: 136 # electrons: 86. We can use a similar notation for protons, neutrons, electrons and positrons (positively charged electrons): Protons : Neutrons :

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Nuclear Structure and Radioactivity

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  1. Nuclear Structure and Radioactivity

  2. Atomic Notation Review Example: Element: Radon # protons: 86 # neutrons:136 # electrons: 86

  3. We can use a similar notation for protons, neutrons, electrons and positrons (positively charged electrons): • Protons: Neutrons: • Electrons: Positrons:

  4. Radiation: • Positively charged protons in atomic nuclei tend to repel each other. • Nuclei require short range strong nuclear forces between protons and neutrons to dilute the repulsion and act as a nuclear “glue”. • Nuclei having too few (or too many) neutrons are unstable and may release particles (radiation) in order to reach a stable configuration (radioactive decay).

  5. Alpha Decay (α) : • A heavy nucleus decays, producing a smaller nucleus and an alpha particle (a helium nucleus, having 2 protons and 2 neutrons) • General Form: • Example (complete what’s missing):

  6. Beta Decay (β-): • In the first case of beta decay, one neutron converts to a proton plus an electron, and the electron is ejected: , which leads to General Form: Example (complete what’s missing):

  7. Beta Decay (β+): • In the second case, a proton converts to a neutron and a positron: , which leads to • General Form:

  8. Electron capture and Gamma Ray Emission (γ) • A nucleus may capture an electron, converting a proton to a neutron, but also exciting the nucleus to emit high energy gamma rays: • General Form: A-1 Z+1

  9. Ionizing radiation • consists of waves or particles that carry enough energy to remove an electron from an atom or molecule, turning it into a positive ion. • ionizing radiation can cause cell damage, or alter the bonds in a strand of DNA causing problems if the cell reproduces.

  10. Gamma rays do not ionize atoms directly, but they can cause atoms to emit other particles that will cause ionization.

  11. Nuclear Radiation • ionizing radiation emitted from the nucleus of an atom.

  12. Decay Half-Life • Decay of an individual particle is spontaneous and hard to predict • Decay rate of a large sample is easier to track • Half-life is a measure of the average time for a sample to decay to half of its original mass

  13. Half-Life Example • Each isotope has a different half-life • Cobalt-60 has a half-life of 5.27 years

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