Studied by 2 peopleWhat is Nuclear Chemistry?
The study of the atomic nucleus, its reactions, and radioactivity
What is a chemical reaction?
a change in compounds because of forming or breaking molecular bonds
What is a nuclear reaction?
a change in elemental identity because of radioactive decay, fission, or fusion
In chemical reactions, reactions form new...
substances based on the elements present in the reactants
In chemical reactions, energy changes are...
relatively small
In chemical reactions, energy comes from...
breaking and forming chemical bonds
In chemical reactions...
valence electrons drive the reaction
In nuclear reactions, reactions form new...
isotopes or elements
In nuclear reactions, energy changes are...
extremely large
In nuclear reactions, energy comes from...
the binding energy of the nucleus
In nuclear reactions...
a change in the nucleus drives the reaction
What competing forces exist within a nucleus?
Repulsive Coulombic forces (+p repel each other) and nuclear strong forces (holds it together)
What determines the stability of a nucleus?
The ratio of protons to neutrons
Above what number of protons are atoms all unstable?
84
What usually stabilizes a large atom?
The addition of neutrons
Above the band of stability...
isotopes have too many neutrons
Below the band of stability...
isotopes have too many protons
Isotopes above and to the right of the band of stability....
have too many protons and neutrons
Radioactive decay is...
spontaneous disintegration of an unstable nucleus often resulting in the formation of a new element
What determines the probability of when an atom will decay?
An atom's nuclear half life
What are nuclear half-lives?
A calculation of at what time half of a sample will have decayed
Which is possible: a prediction of a nucleus's decay time or a prediction of a sample's decay time?
A sample's decay time
Why does carbon dating with the isotope carbon-14 work?
Because living organisms have the same ratio of carbon-12 to carbon-14 as in the atmosphere, the older a sample is (up to 50,000 years) the less carbon-14 it will have (living organisms absorb carbon-14 by breathing)
Type the particle notation for carbon dating.
147N + 10n -> 146C +11p
What is the attractive force that holds nuclei together?
The nuclear strong force
Nuclear fission is...
a nuclear reaction in which a neutron splits a large nucleus into two or more smaller nuclei releasing a large amount of energy and extra neutrons
Where does nuclear fission occur?
In nuclear power plants and atom bombs
Nuclear fusion is...
a nuclear reaction in which two or more smaller nuclei are combined to form one larger nucleus releasing more energy than fission
What is required for fusion?
Extremely high temperature and pressure
Where does fusion occur?
Fusion occurs in stars and hydrogen bombs
Nuclear fission and fusion both work when nuclei split or combine into....
new atoms with more binding energy
Why does fusion release more energy than fission?
Because fusion combines atom's nuclear strong force which is stronger than the energy released when an atom splits
Which atom has the highest binding energy?
Fe-56
Elements that are smaller than Fe-56 release energy through...
fusion
Elements that are larger than Fe-56 release energy through...
fission
Type the particle notation for a proton.
11p
Type the particle notation for a neutron.
10n
Type the particle notation for an alpha particle.
42He or 42a
Type the particle notation for a bata particle.
0-1e
Type the particle notation for a gamma particle.
00Y
Type the particle notation for a positron.
11e
What is alpha decay?
when an atom loses an alpha particle because it has more than 83 protons
What material can stop the penetration of alpha decay?
Paper, skin, or clothes
What is beta decay?
when a atom with too many neutrons loses an electron by converting a neutron into a proton, releasing an electron
What material can stop the penetration of beta decay?
aluminum foil
What is gamma radiation (decay)?
when an atom has excess energy and releases a gamma wave
What material can stop the penetration of gamma radiation?
Several inches of lead or feet of concrete
What is neutron emmission?
When an atom that is too heavy and above the band of stability sheds a neutron
What material can stop the penetration of a neutron?
Hydrogen-rich material (eg. water)
What is electron capture?
When an atom that is too light and below the band of stability captures an electron to convert a proton into a neutron and releases gamma radiation
What is positron emmission?
When an atom that is too light and below the band of stability emits a positron (opposite of beta decay)
What is a decay series?
a series in which a radioactive nucleus will decay repeatedly into a stable element
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