1. LECTURE 10.4 – RADIOACTIVE DECAY

2. Today’s Learning Targets
LT 9.3 – I can compare and contrast normal isotopes and radioactive isotopes. I can discuss the three forms of decay that radioactive isotopes can undergo and how the nucleus is altered in each type of decay.
LT 9.4 – I can list the three different type of radiation and the impact that each one of these types of decay can have on myself and other living matter

3. What is radioactive decay?

4. I. Radioactive Decay Atoms can be unstable and breakdown
Radioactive Decay – The spontaneous breakdown of the nucleus into a smaller nucleus, accompanied by the release of particles, radiation, or both.

5. What are the 3 types of radioactive decay?

6. I. Alpha (α) Decay Alpha Decay – When an atom splits its nucleus into:
A smaller nucleus and
A Helium atom (2 protons, 2 neutrons).
Observed often in very heavy atoms
Alpha particles on travel a few cm in air
Paper blocks alpha particles

8. Alpha Radiation

9. II. Beta (β) Decay
Some elements are unstable because their proton to neutron ratio is too large.
Beta decay converts neutrons to protons and releases an electron known as a beta particle
neutron  proton + β
Travel a few meters in the air
Metals provide a shield against beta radiation.
Electron

11. Beta Radiation

12. III. Gamma (γ) Decay
Gamma rays are high energy waves that are released when nucleus goes from high energy state to low energy.
Gamma radiation is the most dangerous. It can lead to DNA mutations and cancers.
Gamma radiation requires thick pieces of lead/concrete in order to stop.

14. Gamma Radiation

15. Radiation Summary Type of Radiation Description Blocked by? Alpha (α)
Beta (β)
Gamma (γ)
The spitting of a nucleus into a smaller nucleus and a He atom (alpha particle
Blocked by paper
Converts a neutron to a proton and an electron (beta particle)
Blocked by metals
High energy waves that are released by nucleus
Blocked by lead

16. Class Example Label the following decay as alpha, beta or gamma decay
4319K  4320Ca + electron

17. Table Talk Label the following decay as alpha, beta or gamma decay
21084Po  20682Pb + 42He

18. Table Talk Complete the following reaction if it undergoes beta decay: