radioactivity

• Radioactive decay: A radioisotope (unstable arrangement of neutrons and protons) is altered to make a more stable arrangement.
• In radioactive decay, the parent nucleus becomes a daughter nucleus and a particle (decay products).
• The three types of radiation are alpha particles, beta particles, and gamma rays.
• In β+ decay, a proton decays to a neutron and a positron. the positron (β+ particle) is emitted from the nucleus, carrying away a positive charge.
• in β- decay, a neutron decays to a proton and an electron. The electron(β- particle) is emitted from the nucleus.
• β- decay

  
  

  n -> p + e-

  example:

  14 C -> 14 N + 0 e

  6 7 -1
• β+ decay

  p -> n + e+

  example:

  22 Na -> 22 Ne + 0 β

  11 10 1
• gamma radiation has no effect on the mass or charge of a nucleus
• alpha decay reduces mass by 4 and charge by 2

  
  

  238 U -> 234 Th + 4 ⍺

  92 90 2
• Half life is the time it takes for half of the unstable atoms to decay.
• Gamma(γ):

  Nature: Electro-magnetic radiation

  Charge: none

  Penetration: Only reduced by lead

  Effect from fields: not deflected

  Ionizing effect: very weak

  Speed: speed of light