Nuclear Symbols Element symbol Mass number (p + + n o ) Atomic number (number of p + )
Post on 02-Jan-2016
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Types of Radioactive DecayTypes of Radioactive Decay
alpha production (): helium nucleus
• •
beta production ():
92238
24
90234U He Th
90234
91234
10Th Pa e
24
He
10 e
2+
Types of Radioactive DecayTypes of Radioactive Decay
gamma ray production (): •
positron production : • electron capture: (inner-orbital electron is captured by the nucleus)
92238
24
90234
002U He Th
1122
10
1022Na e Ne
80201
10
79201
00Hg e Au
10 e
Type of radiation
emitted & symbol
Nature of the radiation
Nuclear Symbol
Penetrating power, and
what will block it
Effect of release of particles from the
nucleus
Alpha
a helium nucleus of 2 protons and 2 neutrons, mass = 4, charge = +2
Low penetration stopped by a few cm of air or
thin sheet of paper
Reduces the atomic mass number by 4
Reduces the atomic number by 2
Beta
high kinetic energy
electrons, mass =
1/1850 of alpha, charge = -1
Moderate penetration, most stopped by a few mm of metals like
aluminum
Is the result of neutron decay and
will increase the atomic number by 1 but will not change the mass number
Gamma
very high frequency
electromagnetic radiation, mass = 0, charge = 0
Very highly penetrating,
most stopped by a thick layer of
steel or concrete, but even a few
cm of dense lead doesn't stop all of
it!
Is electromagnetic radiation released from an excited
nucleus. The atomic number and mass
number do not change.
Deflection of Decay ParticlesDeflection of Decay Particles
Opposite charges_________ each other.
Like charges_________ each other.
attract
repel
NuclearNuclearStabilityStability
Decay will occur in such a way as to return a nucleus to the band (line) of stability.
A A Decay Decay SeriesSeries
A radioactive nucleus reaches a stable A radioactive nucleus reaches a stable state by a series of stepsstate by a series of steps
Nuclear Fission and FusionNuclear Fission and Fusion
•Fusion: Combining two light nuclei to form a heavier, more stable nucleus.
•Fission: Splitting a heavy nucleus into two nuclei with smaller mass numbers.0
192
23556
1423691
013n U Ba Kr n
23
11
24
10He H He e
Energy and MassEnergy and MassNuclear changes occur with small but measurable losses of mass. The lost mass is called the mass defect, and is converted to energy according to Einstein’s equation:
E = mc2 m = mass defect E = change in energy
c = speed of light
Because c2 is so large, even small amounts of mass are converted to enormous amount of energy.
Chemical Fission Fusion
Sample Reaction C + O2 -> CO2 n + U-235 -> Ba-143 + Kr-91 + 2 n H-2 + H-3 -> He-4 + n
Typical Inputs (to Power Plant) (Fuel)
Bituminous Coal UO2 (3% U-235 + 97% U-238) Deuterium & Lithium
Typical Reaction Temperature (K)
700 K 1000 K 108 K
Energy Released per kg of Fuel (J/kg)
3.3 x 107 J/kg 2.1 x 1012 J/kg 3.4 x 1014 J/kg
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