1. Warm Up 10-12-17 Why are some isotopes radioactive?
Ultraviolet have longer wavelength than gamma ray, which radiation is worst?
Can radiation be good? 1.
grams after 3 half-life
3. Yes proton therapy
Agenda
-Notes Unit 3-5
-Worksheet nuclear decay
Homework Oct 24 – Xtra Credit due

2. Unit 3-5 Characteristics of Nuclear Decay

3. Characteristics of Some Radiation
Alpha- weakest, a thin barrier can stop (they are big and heavy and can’t travel very far)
Beta- clothing, wood, or aluminum can stop this radiation.
Alpha - -when inhaled or ingested can be dangerous. Alpha particle decay use in smoke detector, pace maker and space probes Gamma is most dangerous (atomic bomb) wear a lead vest when taking dental x-rays
carbon dating video
Discuss with your partner - differences between the three radiation
Gamma- highly energized can be stop by concrete or lead

4. Alpha Decay
Problem: the nucleus has too many protons which cause excessive repulsion.
Solution: In an attempt to reduce the repulsion, a Helium nucleus is emitted.

5. Alpha emission (decay)
4 2 He
Identify the product formed when uranium-238 alpha decays
4 2 He Th U
Determines which atom from the periodic table

6. Beta Decay Problem: too many neutrons not enough protons.
Solution: a neutron is turned into a proton and one electron is then ejected.
Neutron is converted into proton, and a electron is released

7. 0 -1 e + 14 7 N 14 6 C beta emission (decay) 0-1 e
Identify the product formed when carbon-14 emits beta particle
0 -1 e N
14 6 C

8. Gamma Decay Problem: the nucleus is at too high an energy.
Solution: The nucleus falls down to a lower energy state and, in the process, emits a high energy photon known as a gamma ray.
Emphasis that the energy released is photon (wavelength) not heat, flame test lab electron losing energy, this is the nucleus losing energy photon = gamma ray instead of visible light (red, green, etc…)

9. gamma emission (decay)
00 γ
Identify the product formed when carbon-14 releases gamma rays
0 0 γ C
14 6 C
Discuss cancer, what is it, diagnosis, treatment? photon therapy

10. Assignments
Summary: Why is alpha weaker than gamma radiation? What’s the difference between bad and good radiation?
Nuclear decay worksheet (at least the front page is done before leaving class) - due next class check answers on my website
Good radiation = proton therapy, controlled and directed at the tumor Chemotherapy = drugs to control the tumor from growing

11. Summary of Radiation Alpha radiation: consists of He nucleus
23892 U  42 He Th
Beta radiation: electrons formed by the decomposition of a neutron
146 C  0-1 e N
Gamma radiation: high energy electromagnetic radiation; often emitted with alpha or beta radiation
– radioactive decay

12. Summary of Radiation Property Alpha radiation Beta radiation
Gamma radiation
Composition
Alpha particle (He nucleus)
Beta particle (electron)
High energy EM radiation
Symbol
, 42 He
, 0-1 e 
Penetrating power
low
moderate
Very high
Shielding
Paper, clothing
Metal foil
Lead, concrete