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Chapter 18

Nuclear Chemistry

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Chapter

Map

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Nuclides

Nuclide = a particular type ofnucleus, characterized by a

specific atomic number and

nucleon number

Nucleon numberormass number

= the number of nucleons(protons and neutrons) in the

nucleus of a nuclide.

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Nuclide Symbolism

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Nuclear Stability Electrostatic force = the force that

causes opposite electrical chargesto attract each other.

Strong force = the force betweennucleons (protons and neutrons).

Neutrons increase the attractionfrom the strong force without

increasing electrostatic repulsion

between nucleons.

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Band ofStability

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Alpha Emission

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Beta Emission

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Positron Emission

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Electron Capture

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Gamma Emission

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Nuclear Reactions Nuclear reactions involve changes

in the nucleus, whereas chemicalreactions involve the loss, gain,and sharing of electrons.

Different isotopes of the sameelement may undergo very

different nuclear reactions, eventhough an elements isotopes allshare the same chemical

characteristics.

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Nuclear Reactions(cont.)

Unlike chemical reactions, the ratesof nuclear reactions are unaffected

by temperature, pressure, and the

presence of other atoms to which

the radioactive atom may be

bonded. Nuclear reactions, in general, give

off much more energy thanchemical reactions

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Nuclear

Equations

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General Nuclear Equations

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Half-life = the time it takes for

one-half of a sample to disappear.

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Radioactive Decay Series

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Radiation Effect onBody

Radioactive emissions ionize atoms andmolecules. This also leads to freeradicals (particles with unpairedelectrons).

H2O H2O+ + e

H2O+ + H2O H3O

+ + OH

H2O + e

H

+ OH

These reactive particles react withimportant substances in the body,leading to immediate damage anddelayed problems, such as cancer.

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Uses for RadioactiveNuclides

Cancer radiation treatment

Computer imaging techniques

Radiocarbon dating

Smoke detectors

Food irradiation

Radioactive tracers

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Nuclear Energy Binding energy = the amount of energy

released when a nucleus is formed. Binding energy per nucleon generally

increases from small atoms to atoms with

a mass number around 56. Thus fusingsmall atoms to form medium-sized atoms(nuclear fusion) releases energy.

Binding energy per nucleon generallydecreases from atoms with a massnumber around 56 to larger atoms. Thussplitting large atoms to form medium-

sized atoms (nuclear fission) alsoreleases energy.

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Binding

Energy

per Nucleon

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Nuclear Fission

Ch i

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Chain

Reaction

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Nuclear Reactor

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Nuclear Fusion Powers the Sun