radioactivity
DESCRIPTION
Radioactivity. Radioactivity. The process by which nuclei emit particles and rays These penetrating particles and rays are called radiation. 4. Symbol is 2 He or 2 α. 4. Types of Radiation. Alpha particle-two p + and two n 0 (helium nucleus) - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/1.jpg)
Radioactivity
![Page 2: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/2.jpg)
Radioactivity The process by which nuclei emit particles
and rays These penetrating particles and rays are
called radiation.
![Page 3: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/3.jpg)
Types of Radiation
Alpha particle-two p+ and two n0 (helium nucleus) Changes identity of the atom (drops by two atomic #’s) Little penetrating power (stopped by paper or skin)
Symbol is 2He or 2α4 4
![Page 4: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/4.jpg)
Types of Radiation Beta particle- a high speed e-
Comes from a neutron that breaks apart Changes identity of the atom (up one atomic #) Stopped by Al foil or wood Symbol is -1e or -1β
![Page 5: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/5.jpg)
Types of Radiation Gamma Radiation
High-energy photon emitted as a gamma ray Often emitted along with α or β radiation Does not change identity of the isotope Highly penetrating and very dangerous to
humans
![Page 6: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/6.jpg)
Radioactive Decay as Equations The symbols for the various particles are
shown:
When a radioisotope changes identity, this is called a transmutation reaction.
![Page 7: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/7.jpg)
Half-Life
Every radioisotope has its own rate of decay measured by its half-life. Half-life (t½) is the time required for half the nuclei of
that radioisotope to decay Could be a fraction of a second or billions of years.
![Page 8: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/8.jpg)
![Page 9: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/9.jpg)
Fission When nuclei of some isotopes are hit with
neutrons, they split into smaller fragments. This is fission.
Every time an isotope splits, TREMENDOUS amounts of energy are released.
![Page 10: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/10.jpg)
Fission Chain Reaction In a chain reaction, the neutrons produced
strike other atoms, which produce more neutrons, etc. This is how a nuclear bomb works. It is also how reactors work, but with controls.
![Page 11: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/11.jpg)
Nuclear Reactors Make use of the energy produced by fission.
![Page 12: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/12.jpg)
Nuclear Reactors The fuel rods from reactors, when spent, are a
major waste issue. They are stored indefinitely, or shipped to another
location. They won’t be safe until the isotopes are stable,
which depends on the half-life of the isotope. The next slide has some fuel rod photos.
![Page 13: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/13.jpg)
Fuel Rods
![Page 14: Radioactivity](https://reader035.vdocuments.net/reader035/viewer/2022062519/568151d8550346895dc01397/html5/thumbnails/14.jpg)
Fusion Occurs when nuclei combine to produce a
heavier nucleus. Occurs naturally in the sun. (4 H nuclei become 1 He
nucleus) It is how current nuclear warheads work.