1. Nuclear Chemistry

3. Chemistry I Mrs. Ragsdale
25.1 Nuclear Radiation
Chemistry I
Mrs. Ragsdale

4. Nuclear Radiation
Certain materials are considered “radioactive” because they give off penetrating rays and particles
Nuclear radiation = penetrating rays emitted by nuclear reactions

5. Chemical vs Nuclear Reactions
Chemical Reactions - atoms gain, lose or share electrons in order to become stable
Nuclear reactions – the nuclei of unstable isotopes (called radioisotopes) become stable by emitting large amounts of energy. This allows them to undergo changes and become stable.
Unaffected by catalysts, changes in temperature, or pressure
Chemical Reactions
Nuclear Reactions

6. 3 Main Types of Radiation
Alpha (α)
Beta (β)
Gamma (γ)

7. Alpha Radiation α When a radioactive source emits a helium atom
Consists of two protons and two neutrons
Has a double positive charge
Uranium - 238
238 = 146 neutrons : 92 protons
After alpha decay
144 neutrons : 90 protons
Becomes Thorium 234

8. Beta Radiation β
Beta radiation occurs when an atom either has too many protons or too many neutrons in is nucleus
An electron results from the breaking apart of a neutron in an atom
Discovered by Ernest Rutherford (remember the gold foil guy?)

9. Gamma Radiation High energy photons emitted by radioisotopes
Gamma Radiation is usually emitted whenever Alpha or Beta radiation is emitted

10. Radiation Penetration

11. Radiation Penetration
Gamma radiation penetrates the most through materials
Can only be stopped by several feet of lead

12. Nuclear Decay Radiation – giving off particles and energy
Nuclear Decay – when a isotope nucleus “decays” by giving off neutrons
The point of nuclear decay is to return a radioactive isotope to a stable configuration

13. Band of Stability

14. Transmutation
Converting an atom of one element into an atom of another element.
Occurs by radioactive decay!

15. Half-Life
The time required for one-half of the nuclei of a radioisotope sample to decay to products

16. Calculating Half-Lives
Manganese-56 is a beta emitter with a half life of 2.6 h. What is the mass of manganese-56 in a 1.0 mg sample of the isotope at the end of 10.4 h?

17. Calculating Half-Lives
A sample of thorium-234 has a half life of 25 days. What portion of a 50g sample will remain after 100 days?

18. 25.3 Fission and Fusion of Atomic Nuclei
Chemistry I
Mrs. Ragsdale

19. Nuclear Fission
Splitting a nucleus into smaller fragments by bombarding an isotope with neutrons.
This can lead to a chain reaction of neutrons bombarding the nuclei of nearby atoms.

20. Nuclear Reactors
Use controlled fission to produce heat (useful energy)
Some form of cooling liquid removes the heat and uses it to create steam
The steam turns a turbine to generate electrical energy

21. Nuclear Waste – The Major Problem with Nuclear Energy
Water is used to cool spent rods and act as a radiation shield
Once the spent fuel rods are removed from the nuclear reactor, they continue to produce heat for years later
Problem! It is cheaper to mine more uranium than to fix and reuse these spent rods
So what do we do? Build up nuclear waste!
Most power plants have been forced to create off- site nuclear waste storage facilities.

22. Nuclear Fusion Nuclei are combined to form a nucleus of greater mass
Extremely high energy!!

23. Fusion Reactors – Energy of the Future?
Major Advantages
Able to use abundant sources of fuel
Will NOT leak dangerous radiation
Produce SIGNIFICANTLY less radioactive waste
Reactors are in the experimental phase around the world

25. Taylor Wilson
14 year old creates a nuclear fusion reactor….in his parent’s garage!
i_built_a_nuclear_fusion_reactor