Chapter 10.1b. * What happens during alpha decay? * Nucleus emits 2 neutrons and 2 protons *...
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Transcript of Chapter 10.1b. * What happens during alpha decay? * Nucleus emits 2 neutrons and 2 protons *...
Chapter 10.1b
*What happens during alpha decay?
*Nucleus emits 2 neutrons and 2 protons
*Symbolized as:
=42He
*Starting (reactant) Isotope is known as “mother”
*Ending (product) Isotope is known as “daughter”
Ex: Nuclear equation for alpha decay of uranium-238:(write down following equation)
•Mass number on left = sum of mass numbers on the right
238 = 234 + 4 (Subtract 4 from the Mother to find Daughter)
•Atomic number on left = sum of atomic numbers on the right
92 = 90 + 2 (Subtract 2 from the Mother to find Daughter)
Alpha Decay
Alpha particle
*What happens during beta decay?
*A neutron within the nucleus decomposes and splits into a proton and an electron *The electron is then emitted leaving the proton behind.
*Symbolized as:
1 Neutron 1 Proton + 1 Electron (ejected)*Change from “mother” isotope (reactant) to “daughter” isotope (product):
*Lost 1 neutron & Gained 1 proton
*Mass numbers are same
*emitted beta particle (electron) has insignificant mass
Nuclear equation for beta decay of thorium-234
(write down following equation)
Beta Decay
Beta particle
• Add 1 to the atomic number of the mother to find the daughter
*What happens during gamma decay?
*Nucleus becomes excited
*As it returns to a lower energy state it emits energy as a photon (gamma ray)*Light we cannot see
*Symbolized as:
*Atomic # and mass # stay same.
*Energy in nucleus decreases.
*Often happens during alpha or beta decay.
*Example: Thorium-234 emits both beta particles and gamma rays (abbreviated as ) as it decays.
(write down following equation)
Gamma Decay
Gamma Ray
•Atomic Mass: 210 = ? + 4
(210 – 4 = 206)•Atomic Number: 84 = ? + 2
(84 – 2 = 82)
•Element with atomic number of 82 is lead (Pb)
1. Write a balanced nuclear equation for the alpha decay of thorium-232.
You Try!
1. Write a balanced nuclear equation for the alpha decay of thorium-232.
•Atomic Mass: 232= ? + 4 (232 – 4 = 228)•Atomic Number: 90 = ? + 2 (90 – 2 = 88)•Element with atomic number of 88 is radium
You Try!
2. Write a balanced nuclear equation for the beta decay of carbon-14.
You Try!
2. Write a balanced nuclear equation for the beta decay of carbon-14.
•Atomic Mass: 14 = ? + 0 (14 – 0 = 14)•Atomic Number: 6 = ? – 1 (6 = 7 – 1)•Element with atomic number of 7 is nitrogen
You Try!
3. Determine the “daughter” (product isotope) of americium-241 alpha decay.
Alpha Particle
You Try!
3. Determine the “daughter” (product isotope) of americium-241 alpha decay.
•Atomic Mass: 241 = ? + 4 (241 – 4 = 237)•Atomic Number: 95 = ? + 2 (95 – 2 = 93)•Element with atomic number of 93 is neptunium
You Try!
4. Determine the “daughter” (product
isotope) of strontium-90 beta decay.
Beta Particle
You Try!
4. Determine the “daughter” (product
isotope) of strontium-90 beta decay.
•Atomic Mass: 90 = ? + 0 (90 – 0 = 90)•Atomic Number: 38 = ? + -1 (38 = 39 – 1)•Element with atomic number of 39 is yttrium
You Try!