1. CHAPTER 10
NUCLEAR CHEMISTRY

2. Section 10.1
I. Radioactivity

3. I. Radioactivity
Process in which an unstable atomic nucleus emits charged particles of energy.
A. Nuclear Decay –
Radioisotope - any atom containing an unstable nucleus
*During radioactive decay,
atoms of that element can
change into atoms of a different
element together

4. B. Types of Nuclear Decay
Scientist can detect a radioactive substance by measuring the nuclear radiation it gives off
Nuclear radiation – charged particles and energy emitted from the nuclei of radioisotopes (there are 3 types: alpha, beta, and gamma)

5. 1. Alpha Particles
Alpha particles – a positively charged particle, emitted by some radioactive nuclei that consists of 2 protons and 2 neutrons
Ernest Rutherford- noted for discovering the nucleus, named them “alpha” rays (later he discovered they were particles (2 protons and 2 neutrons)
They didn’t travel trough materials
They remove electrons (ionize) from matter

6. Alpha Decay (42He) 22688 Ra 22286 Rn + 42He 226– 4 = 222
88-2= 86 change in proton number

7. 2. Beta Decay
Beta Particles- an electron emitted during the radioactive decay of a neutron in an unstable nucleus
Fast moving electrons- travel easily through paper ( stop by 3mm aluminum or 10mm of wood)
They ionize atoms – lose energy

8. Beta Decay( 0-1e)
146C N e
14+0=14
6+1= 7

9. 3. Gamma Decay
Gamma rays are waves, not particles. This means that they have no mass and no charge, but can still do damage.
Gamma rays have a high penetrating power – go through 7 cm of lead

10. Alpha-Beta-Gamma

11. C. Effects of Nuclear Radiation
You are exposed to nuclear radiation everyday
Background radiation – nuclear radiation that occurs naturally in the environment
Water, rocks, plants, and animals all contribute to background radiation

13. 2.Dangers of Nuclear Radiation
* Nuclear radiation can ionize atoms in living tissue
The outer skin keeps most radiation out of the body
Nuclear radiation( gamma ray ) can cause burns in the skin and destroys bone marrow cells which red and white blood cells

14. 3.High concentrations of radon gas
Radon 222 is produced in the Earth’s crust.
Outside the level is low BUT overtime a build up in basements produces alpha particles that can be inhaled and cause damage to lung tissue.

16. 4. Radiation exposure over time
Common Symptoms
Decrease in white blood cells
Hair loss
Sterility
Destruction and death of bones
Cancer
Genetic mutations: birth defects

17. Nuclear Power ADVANTAGES-
Nuclear Fission doesn’t produce gaseous pollutants (generates energy)
Generate Electricity
DISADVANTAGES
Possible escape of radioactive isotopes in the environment
Power plants can only operate for 40 years

18. Power plants Power plants can only operate for 40 years
They are expensive to build
Nuclear waste has to be stored safely
These plants have to be built where they are free from earth quakes, little water and barley populated

19. Detecting Nuclear Radiation
Devices that are used to detect nuclear radiation include Geiger counters and film badges .
Geiger counters – uses a gas filled tube to measure ionizing radiation
Film badges – indicates the
the amount of radiation
exposure for the person
wearing the badge

20. Section 10.2
Rates of Nuclear Decay

21. A. Half- Life
Half- Life – time required for half a sample of radioactive decay
How do you find out how old a rock is?

22. Half- life is a measure of how quickly a substance decays

23. B. Radioactive Dating
Carbon reacts with the Oxygen in the atmosphere and forms carbon dioxide
Plants use carbon dioxide during photosynthesis and keep the ratio of carbon-14 to carbon-12 in the atmosphere constant
When something dies, its carbon-14 begins to decay
If the ratio of C14 to C12 in a fossil is ½ of the atmospheric ratio, then the fossil is 1 half-life or about 5730 years old.

24. ARTIFICIAL TRANSMUTATION
SECTION 10.3
ARTIFICIAL TRANSMUTATION

25. A. Nuclear Reactions in the Laboratory
Scientist can perform artificial transmutation by bombarding atomic nuclei with high energy particles such as protons, neutrons, or alpha particles.

26. B. Transuranium Elements
Elements with the atomic numbers greater than 92
All are radioactive
Generally not found in nature
1977, NASA, powered the Voyager 1 and 2 with alpha decay of plutonium

27. C. Particle accelerators
Charged particles can be accelerated to speeds very close to the speed of light.
The fast moving particles are guided toward a target, where they collide with atomic nuclei
Scientist have developed over 300 isotopes with this device

28. Section 10.4
FISSION AND FUSION

29. A. NUCLEAR FORCES
Strong nuclear force is the attractive force that binds protons and neutrons together in the nucleus
Over very short distances, the strong nuclear force is much greater than the electron forces among protons

30. B. Fission Splitting of atomic nucleus into two smaller pieces
Nuclear fission – tremendous amounts of energy can be produced from very small amounts of mass
Converting energy into mass
E=mc2
E=energy
m= mass
c2 = speed of light ( 3.0 x 108m/s)
Lise Meitner- correctly predicted that fission releases large amounts of energy

31. Triggering a chain reaction
Chain reaction – neutrons released during the splitting of an initial nucleus trigger a series of nuclear fissions
Critical Mass - the smallest possible mass of fissionable material that can sustain a chain reaction

32. Nuclear Energy From Fission
Today nuclear power plants generate 20% of electricity in the United States.
The don’t emit air pollutants
Workers have to wear protective clothing

33. Nuclear Chemistry History
1896 – Antoine Becquerel discovers radioactivity in Uranium
1898- Marie and Pierre Curie discover radioactive elements (polonium and radium)
1905- Albert Einstein - E=mc2 provides the basis for nuclear power
1932 – First atom smasher(particle Accelerator) is used by John Cockcroft and Ernest Walton
Otto Hahns & Strassman produced nuclear fission

34. Nuclear Chemistry History
1942 – The first controlled self-sustaining nuclear chain is achieved by Enrico Fermi’s research group in Chicago
1945 – United States explodes first atom bomb in test near Alamagordo, New Mexico
1951 – Electricity from nuclear fission produced at National Reactor Testing Station, Idaho
1960 – Willard Libby wins the Nobel Prize for developing carbon – 14 dating
1986 – Partial meltdown Chernobyl power plant

35. C. Fusion
Fusion is the process in which the nuclei of two atoms combine
Fusion requires extremely high temperatures
Fusion may someday provide an efficient and clean source of electricity
Scientist face two problems in designing a fusion reactor: they need to archive the high temperature required to start the reaction and they must contain plasma