nuclear reaction and radioactivity

8/13/2019 Nuclear Reaction and Radioactivity

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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

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