Radioactive Decay
What do we call the particles and energy emitted from a radioactive nucleus?
Nuclear radiation
What two things must add up to the same total on both sides of a nuclear equation?
Mass number and atomic number
Half-life is a measure of the amount of _______ to decay.
Time
What is the heaviest stable isotope in existence?
Lead-208 (208Pb)
What is nuclear fusion?
The combining of smaller nuclei to create a larger nucleus.
What decay includes the ejection of a helium nucleus?
Alpha decay
If an isotope undergoes alpha decay, what will happen to its mass number?
It will decrease by 4.
Which of the following is the most radioactive?
Copper-62 (half-life = 540 seconds)
Cobalt-62 (half-life = 92 seconds)
Iron-62 (half-life = 68 seconds)
Manganese-62 (half-life = 0.092 seconds)
Manganese-62 (it has the shortest half-life)
Stable isotopes lighter than Calcium (Z=20) usually have a neutron-to-proton ratio of _________, while heavier isotopes have a ratio greater than that, but less than ___________.
1:1
1.5:1
What decay mode transforms a neutron into a proton?
Beta (-) decay
If a nucleus emits a gamma photon, what will happen to its mass?
Nothing
What percent of a radioisotope will remain after 16 days if the half life is 2 days?
0.39%
In order to confirm if an isotope is STABLE, you need to check this resource.
This is defined as the energy required to disassemble an atomic nucleus OR the energy released when an atomic nucleus is formed.
Nuclear binding energy
What name is given to the particle with the same mass as an electron but with the opposite charge?
Positron
Determine the missing isotope:
7738Sr --> 0+1e + _______
7737Rb
How much of a 520 gram sample of Phosphorus-33 will remain after 76.05 days if the half-life is 25.35 days?
65 grams
Explain why 94Ag is radioactive.
It's neutron-to-proton ration is 1:1 which is too low for a heavier isotope like this. It will go through _______ decay to become more stable.
Why are nuclear reactors on Earth powered by fission and NOT fusion?
Fusion requires very high temperatures and pressures and is very difficult to control.
List the modes of radioactive decay from greatest to least energy (greatest first, least last).
Gamma, Beta (+ and -), Alpha
What type of decay is shown in the equation below?
3714Si --> ______ + 3715P
Beta (-)
What is the half-life of Sodium-24 if a 230.4 gram sample decays to 7.2 grams in 74.8 hours?
14.96 hours
What mode of decay will 102Nb undergo to become more stable?
Beta (-)
Explain why fusion releases more energy than fission using the binding energy curve.
There are large difference in binding energy for lighter elements, which must go through fusion to yield energy. Heavier elements, which must go through fission, have much smaller differences in binding energy. This means fusion can release more energy than fission.