The Nucleus. Compare the benefits and dangers of radioactivity. Which isotopes are used for treatments of which illnesses? How is background radioactivity different from natural radioactivity? How did the transuranium elements come into existence? Does fusion or fission produce more energy?
Which isotopes are used for treatments of which illnesses?
How is background radioactivity different from natural radioactivity?
How did the transuranium elements come into existence?
Does fusion or fission produce more energy?
What are the equations for fission and fusion?
Which reaction has not been achieved and which one is used in nuclear power plants (fission or fusion)?
Compare fission and fusion.
What is the shielding effect?
Write and balance equations that involve alpha, beta, neutron, positron, or proton particles and gamma radiation.
Which direction will alpha particles move when placed in an electric field?
What is the band of stability?
What is the difference between and artificial and natural transmutation?
Use table N and O to solve problems.
Solve problems involving half-life using the equation or the “walk-the-dog” method.
Half-life is constant!
What is a Geiger counter used for?
How do scientist use uranium isotopes to date rocks?
How do scientist use carbon isotopes to date mummies?
Why do doctors use radioisotopes with shorter half-lies when performing a medical procedure?
Which radioisotope is used for sterilizing things like medical equipment?
Which isotope is used in the irradiation of meat?Nuclear Concepts to Master
Radioactive decay of Uranium
LESS harmful to the body
MORE harmful to the body
Ionization is the ability of an atom to become an ion (charged particle).
If electrons are lost a cation is formed.
If electrons are gained an anion is formed.
Ionization is the ability of an electron to jump away from or to another atom.
31H = H31 =H3= H-3
In the band of stability, atoms are stable. The ratio n/p is 1 for low nuclear masses and it increases steadily up to 1.5 for high nuclear masses.Unstable Nucleus?
In region A, a nucleus with too many neutrons is unstable because not enough of them are paired with protons.
In region B, a nucleus with too many protons has too much repulsive electrical interactions to be stable.
Calculate ATOMIC MASS
The colors indicate uranium concentrations: red is high, yellow is medium, blue is low.
The earth is radioactive (air, water, and soil).
Due to elements that spontaneously and uncontrollably emit radioactivity.
Radioactive elements are also called:
Gamma radiation released with beta decay
Protect you from radiation. Distance is also a shield.
Control rods needed in nuclear power plants! WHY? It’s a CHAIN REACTION
Produces hazardous waste since nuclear fuel rods last about 3 years.
The used rods are stored underground
As of 2000, the amount stored is 40000 metric tons
Little to no hazardous waste (He released and no reactor core)
Inexhaustible energy – 1 gallon of sea water contains enough deuterium to support a family of 4 for 1 year.
Why? It’s a CHAIN REACTIONCompare
The time taken for a given sample of a radioisotope to decay so that its radioactivity is one half the initial amount is called the half-life, t½, of that isotope.
The half-life is a constant for the isotope, and shows enormous variations from one isotope to another.
For example, 17F (fluorine-17) has a half-life of 70 seconds, while 238U has a half-life of 4.51 x 109 years. 14C (carbon-14) has a half-life of 5668 years.
The long-lived nature of some waste products of nuclear reactors pose grave ecological problems, as some of these radioisotopes remain dangerously active for tens of thousands of years.
Whereas the short-lived nature of some radioisotopes allow their use in medicine.Half – Life of Radioisotopes
What’s the half-life of Sr-90?
What type of curve is the above?
What would the graph look like if the
The y-axis was % being transformed?
How much 42K will be left in a 320 g sample after 62 h?
Step 1: Look up the half life in Table N, the table of Selected Radioisotopes
Step 2: Set up a table showing the mass, time elapsed, the fraction remaining, and number of half lives.
Step 3: Fill in the table with the starting condition(s) and ending when the full time has elapsed. Time will always start with 0. Fraction will always start as 1, and Half-lives will always start at 0.
Step 4: For each half life elapsed:
a) cut the mass in half
b) increase the time by an amount equal to the half life
c) cut the fraction in half
d) add one to the number of half lives
The table below shows how the activity (in counts per second) of a sample of radioactive material varies in time. Plot a graph of activity against time to determine the half-life of the material.
Extremely Beneficial so that its radioactivity is one half the initial amount is called the half-life, t½, of that isotope.
Nuclear power plants
Nuclear power plants released radioactive substances into the atmosphere during nuclear accidents.
Three Mile Island
Geiger Counter so that its radioactivity is one half the initial amount is called the half-life, t½, of that isotope.
Measures radiation as CPM
Counts per minute
the amount of radioactive material (counts) that is released in one minute
Radioactivity will expose film.
The amount of film exposed indicates the level of exposure to radioactivity.Detecting Radioactivity