NUCLEAR CHEMISTRY
What is
Nuclear Chemistry?
–
Nuclear Chemistry is concerned with the changes in the nucleus of elements.
– The nucleus is a collection of particles called protons and neutrons
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Protons and neutrons are in turn made up of particles called quarks.
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The chemical element of an atom is determined by the number of protons,
or the atomic number, Z, of the nucleus.
Nuclear
Chemistry
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Nuclear chemistry is the sub-field of chemistry dealing with
radioactivity, nuclear processes, and transformations in the nuclei of atoms,
such as nuclear transmutation and nuclear properties.
–
They are also used to help determine the mechanisms of chemical
reactions, to trace the movement of atoms in biological systems, and to date
important historical artifacts.
Nuclear
Reaction
–
A nuclear reaction is a process in which two nuclei or nuclear particles
collide, to produce different products than the initial particles.
–
In principle, a reaction can
involve more than two particles colliding, but such an event is exceptionally
rare.
–
The four main types of nuclear reactions are:
•
Fission.
•
Fusion.
•
Nuclear Decay.
•
Transmutation.
Nuclear
Fission
–
Nuclear fission is a process in
which the nucleus of an atom splits into two or smaller nuclei as fission
products, and usually some by-product particles. Hence, fission is a form of
elemental transmutation.
–
The discovery of nuclear fission has opened a new era—the “Atomic Age.”
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When it is not controlled, it leads to the so-called Atomic Bomb. It can lead to an explosion of destructive force.
–
Nuclear fission of heavy elements was discovered on December 17, 1938, by
German Otto Hahn and his assistant Fritz Strassmann, and explained
theoretically in January 1939 by Lise Meitner and her nephew Otto Robert Frisch
–
Two atomic bombs made by the allied powers (USA and UK) from uranium-235
and plutonium-239 were dropped on Hiroshima and Nagasaki respectively early in
August 1945. These brought the long Second World War to a sudden end.
Nuclear
Fusion
–
Nuclear fusion is a reaction in which two or more Atomic nuclei are
combined to form one or more different atomic nuclei and subatomic particles
which are Neutrons or Protons
–
Fusion is the process that powers active the stars or other High
Magnitude stars.
–
An example of nuclear fusion is
the process of four hydrogens coming together to form helium.
–
In 2008, Wilson was the youngest person to achieve nuclear fusion using
an Inertial Electrostatic Confinement (IEC) device. He is often called the Boy
Who Played With Fusion.
Nuclear
Decay
–
Nuclear decay occurs when the nucleus of an atom is unstable and
spontaneously emits energy in the form of radiation. The result is that the
nucleus changes into the nucleus of one or more other elements.
–
Nuclear Decay is also known as Radioactive Decay, Radioactivity and
Nuclear Disintegration
–
Radioactivity also occurs when an unstable atomic nucleus loses energy
by radiation. A material containing unstable nuclei is considered radioactive.
–
An example of a Radioactive substance is Uranium. When radioactive substances like uranium produce
radiation, they create a lot of heat. That heat causes the water in the power plant
to boil, turning turbines and creating electricity.
Nuclear
Transmutation
–
Nuclear transmutation is the conversion of one chemical element or an
isotope into another chemical element, because any element (or isotope of one)
is defined by its number of protons and neutrons in its atoms, i.e. in the
atomic nucleus, nuclear transmutation occurs in any process where the number of
protons or neutrons in the nucleus is changed.
–
Transmutation can be achieved either by nuclear reaction or by
radioactive decay where no outside cause is needed.
Branches
of Nuclear Chemistry
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There are seven branches of Nuclear Chemistry:
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Radiation chemistry.
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Chemistry for nuclear power.
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Study of nuclear reactions.
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The nuclear fuel cycle.
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Kinetics (use within mechanistic chemistry).
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Uses within geology, biology, and forensic science.
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Nuclear spectroscopy.
Kinetics
in Nuclear Chemistry
q
Nuclear Kinetics
q
As with chemical reactions, the
nuclear reactions are not instantaneous and evolve at differing times (ranging
from billions of years to microseconds). Also, as with chemical reactions,
nuclear reactions follow comparable rate laws.
q
Nuclear Kinetics are used in Mechanistic Chemistry.
q
Real-Life Applications of Nuclear Kinetics are PET scans. PET stands for
Positron Emission Tomography. PET scans are a crucial tool in detecting
diseases at an early stage and can also be used by doctors to target their
treatment in more specific and effective ways.
Facts
about Nuclear Chemistry
•
Nuclear power uses fission (splitting atom
nuclei) to produce energy.
•
Nuclear fusion (joining atom nuclei) also has
potential for energy production.
•
Around 6% of the world’s energy and 14% of
the world’s electricity is produced by nuclear power.
•
There are over 400 nuclear power reactors in
use around the world.
•
Around 30 different countries have
operational nuclear reactors.
•
Nuclear reactors are used to power some military submarines and aircraft
carriers
•
The atomic bombing event of Hiroshima and Nagasaki has almost
massacred 146,000
people in Hiroshima and 80,000 people in Nagasaki. That event was a major event
for Nuclear chemistry.
So, Nuclear
reactions can be used for constructive or destructive purposes.
Summary
and Definitions
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Nucleons – neutron and protons.
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Isotopes – atoms with the same atomic number but different mass numbers
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Three isotopes of uranium: uranium-233, uranium-235, uranium-238
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Superscript- mass number
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Subscript -the atomic number.
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Radionuclides – nuclei that are radioactive
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Radioisotopes – atoms containing radionuclides
Presentation is done by Tharini
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