nuclear reaction and radioactivity
TRANSCRIPT
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NUCLEAR REACTION
AND
RADIOACTIVITY
Submitted by:
Ian Joel G. Santiago
Janne Riel B. Santos
Submitted to:
Professor Liwayway Velasquez
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Nuclear transmutation
Transmutation, the changing of one chemical element into another. it involves achange in the nucleus, or core, of an atom and is, therefore, a nuclear reaction. An atom
contains a nucleus that is made up of protons and neutrons and surrounded by electrons.
The number of protons gives the atom its identity as a chemical element. When the number
of protons in an atom is changed, the atom is transmuted into an atom of another element.
Transmutation may be either natural or artificial.
Natural transmutation
It is responsible for the creation of all the chemical elements we observe naturally.
Most of this happened in the distant past. One type of natural transmutation observable in
the present occurs when certainradioactiveelementspresent in nature spontaneously decay
by a process that causes transmutation, such as alpha or beta decay.
Artificial Nuclear Transformations
It is possible, under the right conditions, for us to transform one element into
another. This is done by "slamming" a particle into a nucleus, causing the nucleus tochange and therefore the identity or the mass of the atom. Alpha particles can be used to
transform one nucleus into another. Since the nucleus of the alpha particle is positive and
the nucleus of the atom being bombarded is also positive, the particles will naturally repel
each other. In order to over come this repulsion, the reaction must be performed at very
high speeds (speed of light). These speeds are achieved using particle accelerators.
Nuclear fission
Nuclear fission is a nuclear process. It is when an atom splits apart into smaller
atoms. The process gives off a lot of energy, and is used in nuclear weapons andnuclear
reactors.It is either anuclear reaction or aradioactive decayprocess in which thenucleus of
a particle splits into smaller parts (lighternuclei). The fission process often produces free
neutrons and photons (in the form of gamma rays), and releases a very large amount of
energy even by the energetic standards of radioactive decay.
http://en.wikipedia.org/wiki/Radioactivehttp://en.wikipedia.org/wiki/Chemical_elementshttp://simple.wikipedia.org/wiki/Nuclear_reactionhttp://simple.wikipedia.org/wiki/Atomhttp://simple.wikipedia.org/wiki/Nuclear_weaponhttp://simple.wikipedia.org/wiki/Nuclear_reactorhttp://simple.wikipedia.org/wiki/Nuclear_reactorhttp://en.wikipedia.org/wiki/Nuclear_reactionhttp://en.wikipedia.org/wiki/Radioactive_decayhttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Neutronhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Gamma_rayhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Gamma_rayhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Neutronhttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Radioactive_decayhttp://en.wikipedia.org/wiki/Nuclear_reactionhttp://simple.wikipedia.org/wiki/Nuclear_reactorhttp://simple.wikipedia.org/wiki/Nuclear_reactorhttp://simple.wikipedia.org/wiki/Nuclear_weaponhttp://simple.wikipedia.org/wiki/Atomhttp://simple.wikipedia.org/wiki/Nuclear_reactionhttp://en.wikipedia.org/wiki/Chemical_elementshttp://en.wikipedia.org/wiki/Radioactive -
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Fission is a form of nuclear transmutationbecause the resulting fragments are not
the same element as the original atom. The two nuclei produced are most often of
comparable but slightly different sizes, typically with a mass ratio of products of about 3 to
2, for commonfissileisotopes.
In nuclear fission,
A large nucleus is bombarded with a small particle The nucleus splits into smaller nuclei and several neutrons Large amounts of energy are released
When a neutron bombards235
U,
An unstable nucleus of 236U undergoes fission (splits) The nucleus splits to release large amounts of energy Smaller nuclei are produced, such as Kr-91 and Ba-142 Neutrons are also released to bombard more 235U nuclei In a nuclear chain reaction, the fission of each U-235 atom produces three neutrons
that cause the nuclear fission of more and more uranium-235 atoms.
http://en.wikipedia.org/wiki/Nuclear_transmutationhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Fissilehttp://en.wikipedia.org/wiki/Isotopehttp://en.wikipedia.org/wiki/Isotopehttp://en.wikipedia.org/wiki/Fissilehttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Nuclear_transmutation -
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E= mc2
The total mass of the products in this reaction is slightly less than the mass of the
starting materials. The missing mass has been converted into energy, consistent with the
famous equation derived by Albert Einstein,E= mc2.
E is the energy released, mis the mass lost, and cis the speed of light, 3.0 108m/s.
Using this equation, a small amount of mass is multiplied by the speed of light squared,
resulting in a large amount of energy. Fission of 1 g U-235 produces same energy as 3 tons
of coal.
Nuclear fusion
Nuclear fusion is the process of making a single heavynucleus (part of anatom)
from two lighternuclei.This process is called anuclear reaction.It releases a large amount
of energy.[1]
The nucleus made by fusion is heavier than either of the starting nuclei.
However, it is not as heavy as the combination of the original mass of the starting nuclei
(atoms). This lost mass is changed into lots of energy.This is shown inEinstein's famous
E=mc2equation.
http://simple.wikipedia.org/wiki/Nucleus_%28physics%29http://simple.wikipedia.org/wiki/Atomhttp://simple.wikipedia.org/wiki/Nucleus_%28physics%29http://simple.wikipedia.org/wiki/Nuclear_reactionhttp://simple.wikipedia.org/wiki/Energyhttp://simple.wikipedia.org/wiki/Nuclear_fusion#cite_note-1http://simple.wikipedia.org/wiki/Nuclear_fusion#cite_note-1http://simple.wikipedia.org/wiki/Nuclear_fusion#cite_note-1http://simple.wikipedia.org/wiki/Masshttp://simple.wikipedia.org/wiki/Atomhttp://simple.wikipedia.org/wiki/Energyhttp://simple.wikipedia.org/wiki/Einsteinhttp://simple.wikipedia.org/wiki/E%3Dmc2http://simple.wikipedia.org/wiki/E%3Dmc2http://simple.wikipedia.org/wiki/E%3Dmc2http://simple.wikipedia.org/wiki/E%3Dmc2http://simple.wikipedia.org/wiki/Einsteinhttp://simple.wikipedia.org/wiki/Energyhttp://simple.wikipedia.org/wiki/Atomhttp://simple.wikipedia.org/wiki/Masshttp://simple.wikipedia.org/wiki/Nuclear_fusion#cite_note-1http://simple.wikipedia.org/wiki/Energyhttp://simple.wikipedia.org/wiki/Nuclear_reactionhttp://simple.wikipedia.org/wiki/Nucleus_%28physics%29http://simple.wikipedia.org/wiki/Atomhttp://simple.wikipedia.org/wiki/Nucleus_%28physics%29 -
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Occurs at extremely high temperatures (100 000 000 C) Combines small nuclei into larger nuclei Releases large amounts of energy Occurs continuously in the sun and stars
Radiation
It is a process in which energetic particles or energetic waves travel through a
vacuum, or through matter-containing media that are not required for their propagation.
Waves of a mass filled medium itself, such as water waves or sound waves, are usually not
considered to be forms of "radiation" in this sense.
Radiation can be classified as eitherionizing ornon-ionizing according to whether it
ionizes or does not ionize ordinary chemical matter. The word radiation is often
colloquially used in reference to ionizing radiation (e.g.x-rays,gamma rays), but the term
radiation may correctly also refer to non-ionizing radiation (e.g.,radio waves,microwaves,
heat or visible light) as well. The particles or waves radiate (i.e., travel outward in all
directions) from a source. This aspect leads to a system ofmeasurements and physical units
that are applicable to all types of radiation. Because radiation expands as it passes through
space, and as its energy is conserved (in vacuum), the power of all types of radiation
follows aninverse-square law in relation to the distance from its source.
http://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Ionizing_radiationhttp://en.wikipedia.org/wiki/Non-ionizing_radiationhttp://en.wikipedia.org/wiki/X-rayshttp://en.wikipedia.org/wiki/Gamma_rayshttp://en.wikipedia.org/wiki/Radio_waveshttp://en.wikipedia.org/wiki/Microwaveshttp://en.wikipedia.org/wiki/Infrared_radiationhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Radiometryhttp://en.wikipedia.org/wiki/Inverse-square_lawhttp://en.wikipedia.org/wiki/Inverse-square_lawhttp://en.wikipedia.org/wiki/Radiometryhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Infrared_radiationhttp://en.wikipedia.org/wiki/Microwaveshttp://en.wikipedia.org/wiki/Radio_waveshttp://en.wikipedia.org/wiki/Gamma_rayshttp://en.wikipedia.org/wiki/X-rayshttp://en.wikipedia.org/wiki/Non-ionizing_radiationhttp://en.wikipedia.org/wiki/Ionizing_radiationhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Energy -
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In 1896, Henri Becquerel discovered, almost by accident, that uranium can blackena photographic plate, even in the dark.
Uranium emits very energetic radiation - it is radioactive.
Then Marie and Pierre Curie discovered more radioactive elements includingpolonium and radium.
Scientists soon realised that there were three different types of radiation. These were called alpha (), beta (), and gamma () rays from the first three letters
of the Greek alphabet.
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Transmutation
Artificial Transformation The process of striking nuclei with high energy particles in order to change them
into new elements
Natural Vs. Artificial
In Natural Transmutation a nucleus spontaneously decays into another nucleus byemitting one of several particles
Induced or artificial transmutation require one particle to be slammed into anotherto induce the change
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Radioactive Decay
The process in which atomic nuclei emit particles or rays to become lighter and
more stable.
The spontaneous breakdown of an unstable atomic nucleus.
There are three types of radioactive decay, alpha decay, beta decay and gamma
decay, each determined by the type of radiation released.
Alpha Decay
Occurs when a nucleus releases an alpha particle.
The release of an alpha particle (2 protons and 2 neutrons) decreases the atomic
mass of the nucleus by 4 and decreases the atomic number by 2.
Example: Uranium-238 has an atomic mass of 238 and an atomic number of 92.
Therefore, it has 92 protons and 146 neutrons (Atomic mass minus atomic number). When
undergoes alpha decay or loses an alpha particle, it changes into an atom of Thorium which
has 90 protons and 144 neutrons.
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Beta Decay
Occurs when a nucleus releases a beta particle.
A beta particle is an electron formed inside the nucleus when a neutron breaks apart.
The other particle that is formed is a proton.
The release of a beta particle increases the atomic number by 1 because of the
additional proton formed.
Example: Carbon-14 has 6 protons and 8 neutrons. When in undergoes beta decay,
it changes to an atom of Nitrogen-14 which has 7 protons and 7 neutrons. The atomic
number of Carbon-14 is 6 and the atomic number of Nitrogen is 7.
Gamma Decay
Alpha and beta decay are almost always accompanied by gamma decay, which
involves the release of a gamma ray.
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When a gamma ray is emitted by a nucleus, the nucleus does not change into a
different nucleus but because a gamma ray is an extremely high-energy wave, the nucleus
makes a transition to a lower energy state.
Radioactive Half-Life
The period of time in which a radioactive element decays.
The amount of time it takes for half the atoms in a given sample of an element todecay.
Example: Suppose you had 20 grams of pure Barium-139. Its half-life is 86 minutes.
So after 86 minutes, half of the atoms would have decayed into another element. You
would have 10 grams of Barium-139. After another 86 minutes, you would only have 5
grams of Barium-139 which is one-fourth of what you originally had.
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Decay Series
The series of steps by which a radioactive nucleus decays into a nonradioactive
nucleus.
Example: The decay series for Uranium-238
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Sources:
http://en.wikipedia.org/wiki/Radioactive_decay
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html
http://en.wikipedia.org/wiki/Nuclear_fission
http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fission.html
http://en.wikipedia.org/wiki/Nuclear_fusion
http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fusion.html
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radser.html
Fundamentals of Physics by Halliday, Resnick and Walker
http://en.wikipedia.org/wiki/Radioactive_decayhttp://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.htmlhttp://en.wikipedia.org/wiki/Nuclear_fissionhttp://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fission.htmlhttp://en.wikipedia.org/wiki/Nuclear_fusionhttp://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fusion.htmlhttp://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radser.htmlhttp://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radser.htmlhttp://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fusion.htmlhttp://en.wikipedia.org/wiki/Nuclear_fusionhttp://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fission.htmlhttp://en.wikipedia.org/wiki/Nuclear_fissionhttp://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.htmlhttp://en.wikipedia.org/wiki/Radioactive_decay