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Chapter Resources. 18. Click on one of the following icons to go to that resource. gpscience.com. Image Bank. Foldables. Video Clips and Animations. Chapter Summary. Chapter Review Questions. Standardized Test Practice. Chapter Resources. 5. gpscience.com. Image Bank. 18.
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Chapter Resources 18 Click on one of the following icons to go to that resource. gpscience.com Image Bank Foldables Video Clips and Animations Chapter Summary Chapter Review Questions Standardized Test Practice
Chapter Resources 5 gpscience.com
Image Bank 18 Click on individual thumbnail images to view larger versions.
Image Bank 18 Transfer Images • To transfer images to your own power point follow the following steps: • Open the “Resource” file from the CD-ROM disc – view the file in the “normal view” or “slide sorter view” mode - go to slide #2 – from there you can click through the images and follow these instructions. Click once on the image. • Copy the image • Go to your own power point document • Paste the image.
Image Bank 18 Nucleus of an Atom
Image Bank 18 Protons Attracted
Image Bank 18 Strong Force Between Protons
Image Bank 18 Strong Force Between Protons
Image Bank 18 Small Nuclei
Image Bank 18 Large Nuclei
Image Bank 18 Helium Isotopes
Image Bank 18 Table – Alpha Particles
Image Bank 18 Smoke Detector
Image Bank 18 Transmutation
Image Bank 18 Table – Beta Particles
Image Bank 18 Beta Decay
Image Bank 18 Table – Gamma Rays
Image Bank 18 Half Life
Image Bank 18 Table – Sample Half Lives
Image Bank 18 Carbon-14 Intake
Image Bank 18 Geiger Counter
Image Bank 18 Geiger Counter
Image Bank 18 Circle Graph – Sources of Background Radiation
Image Bank 18 Nuclear Fission
Image Bank 18 Chain Reaction
Image Bank 18 Nuclear Fussion
Image Bank 18 Thyroid
Image Bank 18 Electroscope
Foldables 18 Radioactivity and Nuclear Reactions Make the following Foldable to help you understand radioactivity and nuclear reactions.
Foldables 18 Fold a vertical sheet of paper in half lengthwise.
Foldables 18 Fold paper down 2.5 cm from the top. (Hint: From the tip of your index finger to your middle knuckle is about 2.5 cm.)
Foldables 18 Open and draw lines along the 2.5-cm fold. Label as shown.
Foldables 18 Summarize in a Table As you read the chapter, write what you learn about radioactivity in the left column, and what you learn about nuclear reactions in the right column.
Video Clips and Animations 18 Click image to play movie To view the next video clip or animation click here.
Video Clips and Animations 18 To view the next video clip or animation click here.
Reviewing Main Ideas 18.1 Radioactivity • The protons and neutrons in an atomic nucleus are held together by the strong force. • The ratio of protons to neutrons indicates whether a nucleus will be stable or unstable. Large nuclei tend to be unstable. • Radioactivity is the emission of energy or particles from an unstable nucleus. • Radioactivity was discovered accidentally by Henri Becquerel about 100 years ago.
Reviewing Main Ideas Reviewing Main Ideas 18.2 Nuclear Decay • Unstable nuclei can decay by emitting alpha particles, beta particles, and gamma rays. • Alpha particles consist of two protons and two neutrons. A beta particle is an electron. • Gamma rays are the highest frequency electromagnetic waves. • Half-life is the amount of time in which half of the nuclei of a radioactive isotope will decay.
Reviewing Main Ideas 18.2 Nuclear Decay • Because all living things contain carbon, the radioactive isotope carbon-14 can be used to date the remains of organisms that lived during the past 50,000 years. • Radioactive isotopes of uranium are used to date rocks.
Reviewing Main Ideas 18.3 Detecting Radioactivity • Radioactivity can be detected with a cloud chamber, a bubble chamber, an electroscope, or a Geiger counter. • A Geiger counter measures the amount of radiation by producing electric current when it is struck by a charged particle. • Background radiation is low-level radiation emitted by naturally occurring isotopes found in Earth’s rocks and soils, the atmosphere, and inside your body.
Reviewing Main Ideas 18.4 Nuclear Reactions • When nuclear fission occurs, a nucleus splits into smaller nuclei. Neutrons and a large amount of energy are emitted. • Neutrons emitted when a nuclear fission reaction occurs can cause a chain reaction. A chain reaction can occur only if a critical mass of material is present. • Nuclear fusion occurs at high temperatures when light nuclei collide and form heavier nuclei, releasing a large amount of energy.
Reviewing Main Ideas 18.4 Nuclear Reactions • Radioactive tracers that are absorbed by specific organs can help diagnose health problems. Nuclear radiation is used to kill cancer cells.
Chapter Review 18 Question 1 What is meant by “radioactive half-life”?
Chapter Review 18 Answer The half-life of a radioactive isotope is the amount of time it takes for half the radioactive nuclei in any sample to undergo radioactive decay. The half-life is independent of physical state, temperature, pressure or other external conditions.
Chapter Review 18 Question 2 What is the percentage of radioactive nuclei left after 4 half-lives pass? A. 50 B. 25 C. 10 D. 6
Chapter Review 18 Answer The answer is D. After 4 half-lives pass, there is one-sixteenth the original sample of radioactive nuclei.
Chapter Review 18 Question 3 Why can background radiation not be completely eliminated? Answer Background radiation comes from naturally occurring processes, so it can never be completely eliminated.
Chapter Review 18 Question 4 What process is represented by the diagram? A. beta decay B. chain reaction C. nuclear fusion D. radioactive decay
Chapter Review 18 Answer The answer is B. A chain reaction occurs when neutrons emitted from a split nucleus cause other nuclei to split and emit additional neutrons.
Chapter Review 18 Question 5 Where is this reaction most likely to occur?
