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Section 4.4. Unstable Nuclei and Radioactive Decay. Objectives. Explain relationship between unstable nuclei and radioactive decay Characterize alpha, beta, and gamma radiation in terms of mass and change. Review. Recall chemical reactions Are new substances formed?
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Section 4.4 Unstable Nuclei and Radioactive Decay
Objectives • Explain relationship between unstable nuclei and radioactive decay • Characterize alpha, beta, and gamma radiation in terms of mass and change
Review • Recall chemical reactions • Are new substances formed? • Were atoms affected/changed? • Chemical reactions only involve electrons • Nucleus is NOT affected in CHEMICAL REACTIONS
Nuclear Reactions • DO change the nucleus • Atoms of one element change into atoms of another
Radioactivity • Substance spontaneously emits radiation • Rays and particles are called radiation • Atoms change into other elements
Unstable Systems • Radioactivity occurs when an atom’s nucleus is unstable • Unstable systems gain stability by losing energy
Radioactive Decay • Unstable nucleus loses energy by emitting radiation spontaneously • Radiates until stable • New atom forms
Types of Radiation • Alpha • Beta • Gamma
Alpha Radiation • Deflects toward a negative charge • Alpha particles • 2 protons & 2 neutrons • 42He or • Blocked by only a thin sheet of paper
Nuclear Equation 22688 Ra 22286Rn + 42He Radium Radon
Beta Radiation • Deflect toward positive charge • Beta particles, • Electron (-1 charge) • Aluminum blocks beta radiation 146C 147N + 0-1
Gamma Radiation • High energy radiation • No mass • No charge • Most dangerous • Accompany or particles • Account for energy lost • CANNOT form new atom on its own 00
Practice 6027Co 6028Ni + ____ 24195Am ____ + 42He
Practice Solution • Complete the following nuclear reactions: 6027Co 6028Ni + 0-1 24195Am 23793Np + 42He