Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei...
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Transcript of Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei...
![Page 1: Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei and radioactive decay. element: a pure substance that.](https://reader031.fdocuments.in/reader031/viewer/2022032105/56649d095503460f949db599/html5/thumbnails/1.jpg)
Section 4.4 Unstable Nuclei and Radioactive Decay
• Explain the relationship between unstable nuclei and radioactive decay.
element: a pure substance that cannot be broken down into simpler substances by physical or chemical means
• Characterize alpha, beta, and gamma radiation in terms of mass and charge.
![Page 2: Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei and radioactive decay. element: a pure substance that.](https://reader031.fdocuments.in/reader031/viewer/2022032105/56649d095503460f949db599/html5/thumbnails/2.jpg)
Section 4.4 Unstable Nuclei and Radioactive Decay (cont.)
radioactivityradiationnuclear reactionradioactive decayalpha radiation
Unstable atoms emit radiation to gain stability.
alpha particlenuclear equationbeta radiationbeta particlegamma rays
![Page 3: Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei and radioactive decay. element: a pure substance that.](https://reader031.fdocuments.in/reader031/viewer/2022032105/56649d095503460f949db599/html5/thumbnails/3.jpg)
Radioactivity
• Nuclear reactions can change one element into another element.
• In the late 1890s, scientists noticed some substances spontaneously emitted radiation, a process they called radioactivity.
• The rays and particles emitted are called radiation.
• A reaction that involves a change in an atom's nucleus is called a nuclear reaction.
• Atoms are radioactive because they have too much energy !!!!
![Page 4: Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei and radioactive decay. element: a pure substance that.](https://reader031.fdocuments.in/reader031/viewer/2022032105/56649d095503460f949db599/html5/thumbnails/4.jpg)
Radioactive Decay
• Unstable nuclei lose energy by emitting radiation in a spontaneous process called radioactive decay.
• Unstable radioactive elements undergo radioactive decay thus forming stable non-radioactive elements.
![Page 5: Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei and radioactive decay. element: a pure substance that.](https://reader031.fdocuments.in/reader031/viewer/2022032105/56649d095503460f949db599/html5/thumbnails/5.jpg)
Balancing Nuclear equations
• The figure shown below is a nuclear equation showing the radioactive decay of Plutonium 239 producing an alpha particle
• The mass is conserved in nuclear equations, meaning the atomic number and mass number must be equal on both sides of the equation.
23994Pu → 42He + _____
![Page 6: Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei and radioactive decay. element: a pure substance that.](https://reader031.fdocuments.in/reader031/viewer/2022032105/56649d095503460f949db599/html5/thumbnails/6.jpg)
Types of Radiation
• Alpha radiation is made up of positively charged particles called alpha particles.
• Each alpha particle contains two protons and two neutrons and has a 2+ charge.
![Page 7: Section 4.4 Unstable Nuclei and Radioactive Decay Explain the relationship between unstable nuclei and radioactive decay. element: a pure substance that.](https://reader031.fdocuments.in/reader031/viewer/2022032105/56649d095503460f949db599/html5/thumbnails/7.jpg)
Types of Radiation
• Beta radiation is radiation that has a negative charge and emits beta particles.
• Each beta particle is an electron with a 1– charge.
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Types of Radiation
• Gamma rays are high-energy radiation with no mass and are neutral.
• Gamma rays account for most of the energy lost during radioactive decay.
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• Gamma Radiation has no mass, so the same isotope is left after radioactive decay
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Radioactive Decay (cont.)
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Radioactive Decay (cont.)
• Atoms that contain too many or two few neutrons are unstable and lose energy through radioactive decay to form a stable nucleus.
• Few exist in nature—most have already decayed to stable forms.