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Basic Chemistry Copyright © 2011 Pearson Education, Inc.1
Chapter 16 Nuclear Radiation
16.1 Natural Radioactivity
A person working with radioisotopes wears protective clothing and gloves and stands behind a shield.
Basic Chemistry Copyright © 2011 Pearson Education, Inc.2
Radioactive Isotopes
A radioactive isotope • has an unstable nucleus• emits radiation to become more stable• can be one or more isotopes of an element• is written with a mass number and an atomic
number• includes the mass number in its name
Example: iodine-131
Basic Chemistry Copyright © 2011 Pearson Education, Inc.3
Examples of Radioactive Isotopes
Basic Chemistry Copyright © 2011 Pearson Education, Inc.4
Learning Check
Thallium-201 is used for heart scans to determine cardiac function.
A. How many protons are in thallium-201?
B. How many neutrons are in thallium-201?
C. What is the atomic symbol of thallium-201?
Basic Chemistry Copyright © 2011 Pearson Education, Inc.5
Solution
Thallium-201 is used for heart scans to determine cardiac function.
A. How many protons are in thallium-201? Thallium, symbol Tl, has 81 protons.B. How many neutrons are in thallium-201? mass number 201 atomic number 81 = 120 neutronsC. What is the atomic symbol of thallium-201? mass number 201 Tl atomic number 81
Basic Chemistry Copyright © 2011 Pearson Education, Inc.6
Nuclear Radiation
Nuclear radiation • is the radiation emitted by an unstable atom• takes the form of alpha particles, neutrons,
beta particles, positrons, or gamma rays
Basic Chemistry Copyright © 2011 Pearson Education, Inc.7
Alpha Particle
An alpha () particle has• a helium nucleus• 2 protons and 2 neutrons• a mass number of 4• a charge of 2+• a low energy compared to
other radiation particles
Basic Chemistry Copyright © 2011 Pearson Education, Inc.8
Beta ParticleA beta () particle • is a high-energy electron• has a mass number of 0• has a charge of 1-• forms in an unstable nucleus when a neutron
changes into a proton and an electron
Basic Chemistry Copyright © 2011 Pearson Education, Inc.9
PositronA positron ( +)• has a mass number of 0• has a charge of 1+• forms in an unstable nucleus when a proton
changes into a neutron and a positron
Basic Chemistry Copyright © 2011 Pearson Education, Inc.10
Gamma () RayA gamma () ray • is high-energy radiation• has a mass number of 0• has a charge of 0• is emitted from an unstable nucleus to give a
more stable, lower energy nucleus
Basic Chemistry Copyright © 2011 Pearson Education, Inc.11
Summary of Common Forms of Nuclear Radiation
Basic Chemistry Copyright © 2011 Pearson Education, Inc.12
Learning Check
Give the mass number and charge of each type of
radiation.
1. alpha particle
2. positron
3. beta particle
4. neutron
5. gamma ray
Basic Chemistry Copyright © 2011 Pearson Education, Inc.13
Solution
Mass Number Charge
1. alpha particle 4 2+
2. positron 0 1+
3. beta particle 0 1-
4. neutron 1 0
5. gamma ray 0 0
Basic Chemistry Copyright © 2011 Pearson Education, Inc.14
Radiation protection requires • paper and clothing for alpha particles• a lab coat or gloves for beta particles• a lead shield or a thick concrete wall for gamma
rays• limiting the amount of time spent near a
radioactive source • increasing the distance from the source
Radiation Protection
Basic Chemistry Copyright © 2011 Pearson Education, Inc.15
Radiation and Shielding Required
Basic Chemistry Copyright © 2011 Pearson Education, Inc.16
Radiation Protection
Different types of shielding are needed for different radiation particles.
Basic Chemistry Copyright © 2011 Pearson Education, Inc.17
Learning Check
Indicate the type of radiation (alpha, beta, and/or gamma) protection for each type of shielding.
1) heavy clothing
2) paper
3) lead
4) lab coat
5) thick concrete
A person working with radioisotopes wears protective clothing and gloves and stands behind a shield.
Basic Chemistry Copyright © 2011 Pearson Education, Inc.18
Solution
Indicate the type of radiation (alpha, beta, and/or
gamma) protection for each type of shielding.
1) heavy clothing alpha, beta
2) paper alpha
3) lead alpha, beta, gamma
4) lab coat alpha, beta
5) thick concrete alpha, beta, gamma