Elementary Particles

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Elementary Particles

• And Nuclear Equations

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Quirks, Quorks, Quarks
Origin of the Name Murray Gell-Mann called them
quorks meaning those funny little things. Other
scientists noting their behavior, called them
quirks. Finally Gell-Mann found a passage in
James Joyces boo Finnegans Wake that referred
to three quarks of Master Mark! He borrowed
the spelling of quark and that is the name used
now.
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Quirks, Quorks, Quarks
It is thought that quarks never appear alone in
nature. They are always found in groups of two
or more. The Top quark was found finally at Fermi
Lab in 1995. The model of quarks which now
remains due to this discovery indicates that
quarks have electric charge, spin and a type of
strong charge called color charge. Scientists
have no decided that quarks come in 6 flavors,
each of which can have one of these colors.
Proton Two up and a down. Up has a positive
charge, down negative 2/3 2/3 1/3 1
charge Neutron down down up -1/3 1/3
2/3 0
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Common Subatomic Species
Name
Symbol
Mass
Charge
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Detection of Elementary Particles

• Particles leave tracks (ionized gas)

• Particles have a specific behavior in electric or
  magnetic fields (linear accelerators).

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Particle Classification
Classification Particle Name
Anti-particle Detected
tau particle e-
leptons
Photons
Electromagnetic energy
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Particle Classification
Classification Particle Name
Anti-particle Detected
hadrons
hyperons (more mass)
100 known
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Particle Half-life

• Nucleons gt protons neutrons

• Nucleus by itself radioactive

• Neutron Half-life 12 min. (1/2 will decay in
  12 min.)

• Proton can exist for a long time.
• p 90 of mass of a star

But!
neutrino
photon

• Probably half-life 1031 years

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Balancing Nuclear Equations
To balance nuclear equations conservation of mass
number and of charge on the nucleus must be
achieved.
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Nuclear Symbols
A Mass Number
Z Positive charge on nucleus
OR
A Sum of protons and neutrons
Z Number of protons
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To Balance Nuclear Equations

• Show conservation of mass number and of charge on
  the nucleus

• Use the nuclear symbols

Emission or absorption radiation symbols

• Alpha
• Beta
• Fission
• Fusion

Left Right
Left Right
Antimatter
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Balancing Nuclear EquationsAlpha Radiation
In a nuclear equation, charge and mass must be
conserved.
238 4 A A 234 92 2 Z Z 90
90 ? Thorium
X
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Balancing Nuclear EquationsBeta Radiation
210 0 A A 210 82 -1 Z Z 83
Isotope is 83 ? Bi
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Balancing Nuclear EquationsFission

• Fission Bombarding nuclei with neutrons to break
  them up into approximately equal, smaller, stable
  nuclei.

(emit neutrons ? Begins chain reaction energy)
235 1 139 94 3(1) 92 0 56 36 3(0)
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Balancing Nuclear EquationsFusion
d. Fusion two nuclei combine to form large, more
stable nucleus.
4(1) ? 4 2(0) 4(1) ? 2 2(1)
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Decay Pattern of U-238 and Half-Life