Transcript Recognize Me?

Nuclear Energy
Nuclear Structure and Radioactivity
I. Review - Periodic Table
A.
Atomic Number:
•
B.
The number of protons in the nucleus of an atom
Atomic Mass:
•
The sum of the mass of protons, neutrons and electrons in the
atom
•
# of neutrons = atomic mass - atomic number
Il. Review - Atomic Structure
Recognize
Me?
A.
Atomic Structure:
•
B.
Atoms contain protons, neutrons and electrons
Isotopes:
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The number of neutrons in an atom is not always the same!
•
Atoms of the same elements that have an abnormal number of
neutrons are called Isotopes.
III. Radioactivity
A.
Definition: The emission of radiation due to the breakdown of atomic nuclei
B.
Description of Process:
•
Isotopes and large atoms are unstable and will break apart
•
New, lighter atoms are formed, releasing radiation in the process
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Unstable atoms will continue to break down until they become stable
IV. Radiation
A.
Definition: Energy that is radiated or transmitted in the form of rays, waves
or particles
B.
Types of Radiation
1.
Alpha () Particle :
•
Nucleus of a helium atom; Charge (+2); Mass of 4
•
Alpha decay occurs because the nucleus has too many protons which
causes excessive repulsion. An alpha particle is emitted to reduce this.
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The atomic # of the decaying atom decreases by 2 and the mass decreases
by 4

Symbol


IV. Radiation
B.
Types of Radiation
2.
Beta ( Particle :
•
High speed electron
•
Charge (-1); No measurable mass
•
Beta decay occurs when the neutron to proton ratio is too great and causes
instability. A beta particle is emitted, converting a neutron into a proton.
•
The atomic # of the decaying atom increases by 1and the mass does not
change

Symbol


IV. Radiation
B.
Types of Radiation
3.
Gamma ( ) Ray :
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High energy photon (wave)
•
No charge; No measurable mass
•
Gamma decay occurs because the nucleus is at too high an energy. A
gamma ray is emitted as the nucleus falls to a lower energy state.
•
The atomic number and mass of the decaying atom do not change
Symbol



Radiation Summary Slide
V. Energy Generated From Nuclear Fission
A.
Definition: The splitting of large atomic nuclei into smaller fragments
B.
Description of Process:
•
A large atom is struck by a single neutron
•
Fission products include smaller atoms, neutrons and heat energy
•
Uranium-235 is the most common isotope used to generate useable
nuclear energy in power plants
VI. Energy Generated From Nuclear Fusion
A.
Definition: The combining of small atomic nuclei to form larger ones
B.
Description of Process:
•
The mass of the combination is less than the sum of the masses of the
individual nuclei. Mass is converted into energy!
•
Takes place continuously in the sun and stars (H is converted into He)
•
For energy production on earth, the nuclei of two isotopes of hydrogen
are used: Deuterium and Tritium
C.
Energy Released from Nuclear Fusion:
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10 grams of Deuterium which can be
extracted from 500 liters of water
could produce enough fuel for the
lifetime electricity needs of an
average person in an industrialized
country.
•
Do we use fusion to generate
electricity?