unit 6 radioactivity and nuclear decay

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Unit 6 Radioactivity and Nuclear Decay. Nuclear Changes. Chapter 10.1. What is Radioactivity?. Radioactivity. Radioactivity. Radioactive decay is the disintegration of an unstable atomic nucleus into one or more different nuclides . - PowerPoint PPT Presentation

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Nuclear Changes

Unit 6Radioactivity and Nuclear DecayNuclear ChangesChapter 10.1What is Radioactivity?

Radioactivity

RadioactivityRadioactive decay is the disintegration of an unstable atomic nucleus into one or more different nuclides. After radioactive decay, the element changes into a different isotope of the same element or into an entirely different element.

RadioactivityNuclear radiation is the release of particles from the nucleus during radioactive decay.These particles can either be alpha, beta, or gamma particles.

Types of RadiationAlpha particles can be stopped by paper.Beta particles can be stopped by aluminum.Gamma particles can be stopped by lead.

Alpha DecayAlpha particle () is a positively charged particle that consists of two protons and two neutrons and that is emitted from a nucleus during radioactive decay.This is a helium nucleus.

Beta DecayBeta particle () is an electron or positron that is emitted from a nucleus during radioactive decay.A positron is a positively charged electron, NOT a proton.

Gamma DecayGamma ray () is a high-energy photon emitted by a nucleus during fission and radioactive decay.A photon is a packet of electromagnetic radiation or energy.

Neutron EmissionNeutron emission consists of matter that is emitted from an unstable nucleusNeutrons have no charge, and therefore do not want to interact with other particles.

How old are rocks?If you were asked to determine the age of a rock, you would probably not be able to do so easily.How, then, would you go about finding the rocks age?

Radioactive Decay RatesOne way to find the age involves radioactive decay.It is possible to predict the time required for half of the nuclei in a given radioactive sample to decay.Half-life is the time required for half of the sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope.

Half-Life and Exponential DecayThe definition of half-life tells us that after the first half-life time of a radioactive sample has passed, half of the sample remains unchanged.After the next half-life, half of the remaining half decays, so only a quarter of the original element remains.Of that quarter, half will decay in the next half-life, so only one-eighth will remain unchangedThis relationship is called exponential decay.

Half-life Time Frames

Half-Life Equations

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