1. “More illness is caused by improper water than any other reason and largely because radioactivity is lost from our daily supply of drinking water. "By the patented composition of highly selected and scientifically compounded radium ores of which the Revigator is made, this lost element is perpetually restored to all drinking water placed therein."

2. Nuclear Chemistry Radioactive decay:
Unstable isotopes (radioisotopes) have either too many or too few neutrons
They become stable by releasing energy in the form of radiation particles
Radioisotope:
An unstable isotope of an element
Discovery:
1896, by Becquerel. He studied the phenomenon with his partners Pierre and Marie Curie
Marie coined the term “radioactivity”

3. Radioactive decay: Penetrating power:
The ability of a radiation particle to penetrate through matter
Ionization ability:
The ability of a radiation particle to knock an electron off of an atom it strikes (ionization)

4. 4 +2 -1 +1 Alpha particle Beta particle Positron Gamma ray
TYPE OF PARTICLE
SYMBOL
MASS
CHARGE
PENETRATING POWER
IONIZING ABILITY
Alpha particle
Beta particle
Positron
Gamma ray
Stopped by paper
 or 4 +2
High
- or -1
Moderate
Moderate
+ or +1
Very high
Very low

5. particle: Composed of two protons and two neutrons
Identical to a helium nucleus
A high-energy electron
A high-energy photon (particle of light)
Similar to x-rays

6. Natural transmutation:
A change in a nucleus’ number of protons due to radioactive decay
One element can change into another one

7. Factors Affecting Rate Subatomic Particles Involved
Comparison of Chemical And Nuclear Reactions (In Nature)
CHEMICAL
NUCLEAR
Energy Transfer
Factors Affecting Rate
Spontaneous?
Subatomic Particles Involved
Can be endo- or exothermic
Always exothermic
Temperature, nature of reactants, concentration, etc
Rate cannot be changed
Requires activation energy
Always spontaneous
Nucleons (protons and neutrons)
Valence electrons

8. Artificial transmutation:
A nucleus of one element is bombarded by high energy particles, changing it into a different element
Particle accelerator: Uses electric and magnetic fields to accelerate charged particles close to the speed of light and then smash them into another nucleus
Transuranium elements:
All elements past 92
Created artificially via particle acceleration. Do not exist in nature

9. Solving half-life problems:
The amount of time it takes for half of the nuclei of a given radioisotope to undergo decay
Different for each radioisotope (See Table N)
Cannot be changed by any means
# of half lives:
100%
Amount
Remaining:
Solving half-life problems:
To calculate the number of half-lives that have gone by:
number of half-lives =
Total time
Half-life

10. Click for animation

12. Radioactive dating:
Since radioisotopes decay at a known rate, we can use the remaining amount to determine a sample’s approximate age

13. Nuclear fission and fusion:
Mass defect:
The difference between the mass of an atom and the mass of the sum of its protons and neutrons
The missing mass is converted into energy according to E=mc2

14. Nuclear fission:
For large atoms, the mass of the whole atom is greater than the sum of its protons and neutrons
A neutron strikes a nucleus (usually U-235 or Pu-239), splitting it into two smaller nuclei, accompanied by the release of several neutrons and a lot of energy
Ex:
Chain reaction: An atom undergoes fission and releases several neutrons. These neutrons strike other atoms, causing them to undergo fission. Requires a critical mass of fissionable material

15. Click For Animation

16. Uncontrolled fission:
Controlled vs. Uncontrolled Fission
Uncontrolled fission:
A nuclear bomb
The entire chain reaction is completed in a fraction of a second releasing enormous energy
Uranium-235 Fission Bomb
Plutonium-239 Fission Bomb
Controlled fission:
Nuclear reactor
Excess neutrons are absorbed by control rods, slowing the chain reaction
Heat from the reaction is used to generate electricity
Fuel rods: Either U-235 or Pu-239. A critical mass of fissionable material is required

17. Nuclear fusion: Two nuclei are joined to become one
Releases 1000 times the energy of fission
Requires conditions of enormous temperature and pressure
Ex:
Uncontrolled fusion: a hydrogen (thermonuclear) bomb: Uses a fission bomb to generate the high temperature and pressure needed for fusion to occur
Click For Animation
Click For Animation

18. Controlled fusion: currently under research. Not currently feasible
COMPARISON OF POWER GENERATION USING
NUCLEAR FISSION versus NUCLEAR FUSION
NUCLEAR FISSION
NUCLEAR FUSION
Advantages
Disadvantages
Relatively cheap, no burning of fossil fuels, no greenhouse gases
Fuel is cheap and plentiful, no radioactive waste, more energy than fission
Waste products stay radioactive for thousands of years, danger of meltdown or radiation release
Technology has not yet been perfected

19. Uses of radioisotopes:
Medical and scientific:
Radioactive tracer:
A substance where a stable atom has been replaced by a radioactive atom
Used to learn about chemical pathways in biological systems
*NOTE: X-rays are not nuclear in origin
Ex: Iodine-131: Used to image the thyroid gland
Cancer treatment:
Radiation kills rapidly dividing cancer cells

20. Food preservation: Radioactive dating:
Kills bacteria, fungi, and insects without changing the nature of the food
Uses gamma emitters like Co-60 for maximum penetration
Radioactive dating:
Uses known half-lives of radioisotopes to estimate the age of various substances
Half life must be within the same range as the age of the object to be dated
Ex: Carbon-14 used to date fossils and other organic matter

21. Biological hazards of radiation:
Somatic (body) cells:
Cell death  tissue damage
Cell malfunction  cancer
Reproductive cells:
Cell death  sterility
Cell malfunction  genetic defects passed on to future generations