H3
Nuclear Chemistry
The use of nuclear energy to make new materials, radioisotopes, for use in medicine
and industry is investigated in this chapter. The chapter looks at the properties of
different forms of radiation, nuclear decay and the use of nuclear equations to describe
these transmutations.
Radioactivity
The phenomenon of atoms emitting some form of radiation.
Radioisotopes
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Atomic number (Z)
The number of protons in the nucleus of every atom of that
element.
Mass number (A)
The number of protons and neutrons in the nucleus of the
species concerned.
Isotopes
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Also known as radioactive isotopes
The isotopes of elements that emit radiation.
All isotopes of radioactive elements emit radiation.
Unstable nuclei are radioactive
Stable nuclei are not radioactive
Atoms of the same element that have different numbers
of neutrons in the nuclei of the atoms.
Isotopes have the same atomic number but different mass
numbers.
Unstable isotopes
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The atomic number is greater than 83
The ratio of neutrons to protons places it outside the zone
of stability.
Alpha radiation
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Symbols
Identity
Relative charge
Relative mass
Penetrating power
Beta radiation
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Symbols
Identity
Relative charge
Relative mass
Penetrating power
Gamma radiation
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Symbols
Identity
Relative charge
Relative mass
Penetrating power
, 4He2
helium nucleus
+2
4
low
, 0e-1
electron
-1
1/2000
moderate

electromagnetic radiation
0
0
high
Nuclear equations
The atomic number is written as a subscript to the left of the
symbol and the mass number as a superscript, also to the left.
Nuclear fission
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Also known as splitting the atom
Involves bombarding the nuclei with neutrons
The nucleus is split into two equal fragments and
neutrons with the release of large amounts of energy.
A controlled fission reaction occurs in a nuclear reactor.
Transuranic elements
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Elements with mass numbers greater than 92 (uranium)
Transuranic elements are all artificially made.
Half-life
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The time required for half the atoms in a given sample of
a radioisotope to undergo radioactive decay.
The half-life is independent of the initial mass of the
isotope present.
Detection of radiation
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Photographic film
Cloud chamber
Geiger-Muller tube
Scintillation counter
Uses of radioisotopes
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Cancer treatment
Diagnosis
Thickness gauges in industry
Leak detectors in underground pipes
Irradiation of medical supplies and food
Scientific research as tracers to determine reaction
mechanisms
Domestic smoke alarms
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