Download - Chapter 11 Nuclear Chemistry. 11 | 2 Nuclear Chemistry cont’d What is nuclear chemistry? The study of reactions that result from changes in the nucleus

Chapter 11 Nuclear Chemistry

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Nuclear Chemistry cont’dWhat is nuclear chemistry?

The study of reactions that result from changes in the nucleus of an atom

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Nuclear Chemistry cont’dIn nuclear chemistry specific atoms are called……

……..nuclides.

Nuclides are identified by two types of notation:

1.Nuclear Symbol

2.Element name-mass number

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Nuclear Chemistry cont’d

N15

7

mass number

atomic number

This is an example of a nuclear symbol .

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Nuclear Chemistry cont’dThe nuclear symbol can also be expressed as shown.

mass number

nitrogen-15

name of element

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Nuclear Chemistry cont’dPractice Questions

Write two notations for a nuclidethat has:

a.41 protons, 41 electrons, 55 neutronsb.11 protons, 11 electrons, 14 neutrons

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Radioactive Decay

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Nuclides are either stable or unstable

Unstable nuclides (or radionuclides)undergo radioactive decay.

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Radioactive decay is a nuclear reaction that emits radiation while changing the nuclide of one element into another.

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For example; the silver- 113 radionuclide decays to cadmium- 113 with the emission of a beta particle and gamma rays.

Ag Cd + 113 113

47 48

0

-1

0

0

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Types of Natural Radioactive Emission

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Three major types of natural radioactive emission:

Beta particle (an electron from the nucleus)

Alpha particle( the nucleus of a He atom)

Gamma rays (energy similar to x-rays)

Let’s look at Half-life

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The half-life of a radionuclide is the time required for ½ of it to decay.

Half-life is frequently given the symbol t1/2.

Half-life Decay Graph for 80 mg of Iodine-131

mf = mi

2n

1. mf is the f inal sample mass2. mi is the initial sample mass3. n is number of half -lives

Equation to Determine Final Mass of a Radionuclide

Practice Problem I :

How many grams of cobalt -60 is left when 2.0 g of it decays for 15.9 years? It t1/2 is 5.3 years.

Practice Problem II :

What is the t1/2 for the radionuclide potassium-45 ( a beta emitter) if a 50mg sample decays to 5.3 years.

Let’s look at the Biochemical Effects of Radiation


Nuclear Chemistry cont’dDegree of Penetration by BAG Radiation

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NPenuclear Chemistry cont’d

Alpha .. No damage to skin .. Why? ( greatest damage when ingested… Why?)

Beta ….. Severe burns to skin… Why?

Gamma….. Severe damage to skin and internal organs….. Why?

This is the last powerpoint slide in this chapter

→ Fig. 11.4 Ernest Rutherford was the first person to carry out a bombardment reaction.



→ Table 11.2



CC 11.1 Tobacco RadioactivityNuclear Chemistry cont’d


→ Fig. 11.6 In the U-238 decay series, each nuclide is unstable except Pb-206.



← Fig. 11.7 Ion pair formation.



→ CC 11.2Irridated and nonradiated mushrooms


© Peticolas/Megna/Fundamental Photographs, NYC


← Fig. 11.9 Film badges are used to determine a person’s exposure to radiation.


Doug Plummer/Photo Researchers


Fig. 11.10 Radiation passing through a Geiger counter ionizes one or more gas atoms, producing ion pairs.



← Fig. 11.11 Components of the estimated annual radiation of an average American.



→ CC. 11.3A commercially available kit to test for radon gas in the home.



← Fig. 11.12 Brain scans are obtained using radioactive technetium-99, a laboratory-produced radionuclide.


Science Photo/Custom Medical Stock Photo


← Table 11.4



Table 11.5



→ Fig. 11.13 Cobalt-60 is used as a source of gamma radiation in radiation therapy.


Yoav Levy/Phototake


← Fig. 11.14 A fission chain reaction is caused by further reaction of the neutrons produced during fission.



← Fig. 11.16 The cooling tower at the Trojan nuclear power plant dominates the landscape. The nuclear reactor is housed in the dome-shaped enclosure.


© Albert J. Copley/Visuals Unlimited


→ Fig. 11.17 The process of nuclear fusion maintains the interior of the sun at the temperature of approximately 15 million degrees.


NASA



CAG 11.2


→ CO 11.1Associated with brain-scan technology is the use of small amounts of radioactive substances.


PhotoDisc

← Fig. 11.1 Marie Curie, one of the pioneers in the study of radioactivity, is the first person to have been awarded two Nobel Prizes for scientific work.



→ Table 11.6


Download - Chapter 11 Nuclear Chemistry. 11 | 2 Nuclear Chemistry cont’d What is nuclear chemistry? The study of reactions that result from changes in the nucleus

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