1 / 30

Do Now (5/2/ 12):

Do Now (5/2/ 12):. What is an istope ? What makes an isotope different than its element?. Nuclear Reactions . 5 /2/ 12 . Lesson Objectives . Describe nuclear reactions and perform balancing of nuclear reactions by solving problems. Apply radioactivity equations by solving problems. .

cana
Download Presentation

Do Now (5/2/ 12):

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Do Now (5/2/12): What is an istope? What makes an isotope different than its element?

  2. Nuclear Reactions 5/2/12 

  3. Lesson Objectives • Describe nuclear reactions and perform balancing of nuclear reactions by solving problems. • Apply radioactivity equations by solving problems.

  4. Isotope Atomic nuclei having the same number of protons but different number of neutrons

  5. Vocab Review: Nuclear reaction: A reaction in which the number of protons or neutrons in the nucleus of an atom changes. Atomic number: Number of protons in the nucleus of the atom Mass number: Sum of protons and neutrons in the nucleus of the atom

  6. Format

  7. Alpha decay Radioactive decay process in which the nucleus of an atom emits an alpha particle

  8. Alpha Particle Nucleus of a helium atom

  9. Beta decay Radioactive decay that occurs when a neutron is changed to a proton within the nucleus of an atom, and a beta particle and an antineutrino are emitted

  10. Gamma decay Radioactive process of decay that takes place when the nucleus of an atom emits a gamma ray.

  11. http://library.thinkquest.org/17940/texts/radioactivity/radioactivity.htmlhttp://library.thinkquest.org/17940/texts/radioactivity/radioactivity.html

  12. Mass Defect: The difference between the sum of the mass of the individual nucleon (proton or neutron) and the actual mass.

  13. Example #1: Fermium-253 has a half-life of 0.334 seconds. A radioactive sample is considered to be completely decayed after 10 half-lives. How much time will elapse for this sample to be considered gone?

  14. Binding Energy • The energy equivalent of the mass defect; it is always negative • It is the minimum amount of energy needed to break the nucleus into its component nucleons.

  15. Example #2: The half life of Zn-71 is 2.4 minute. If one had 100 g at the beginning, what is the decay rate of Zn-71?

  16. Mass remaining m=mass remaining Original mass

  17. Example #3: The half life of Zn-71 is 2.4 minute. If one had 100 g at the beginning, how many grams would be left after 7.2 minutes elapsed?

  18. Practice: Use the rest of class to work on the paper: Radioactivity; problems: #2,5,6, and 7

  19. Do Now (4/24/12): Pd-100 has a half-life of 3.6 days. If one had 6.02x1023 atoms at the start, how many atoms would be present

  20. Anti-Matter

  21. Pair Production • When an electron and a positron collide, the two can annihilate each other, resulting in energy in the form of gamma rays. In this process, called annihilation, matter is converted directly into energy. The inverse of annihilation can also occur where energy is converted directly into matter. The inverse of annihilation is called pair production.

  22. Pair Production

  23. The Standard Model • explains what the world is and what holds it together. • explains all the hundreds of particles and complex interactions. • made up of • Quarks • Leptons • Force carriers

  24. Quarks Six flavors (three pairs): up/down, charm/strange, and top/bottom. for each of these quarks, there is a corresponding antiquark. fractionalelectric charge, unlike the proton and electron, which have integer charges of +1 and -1 respectively. Quarks also carry another type of charge called color charge.

  25. Hadrons Composite particles made of quarks individual quarks have fractional electrical charges, so hadrons have a net integer electric charge. no net color charge even though the quarks themselves carry color charge Two classes

  26. Baryons ...are any hadron which is made of three quarks (qqq). Because they are made of two up quarks and one down quark (uud), protons are baryons. So are neutrons (udd).

  27. Mesons ...contain one quark (q) and one antiquark. Ex: pion (π+), which is made of an up quark and a down anitiquark. an antipion(π-) is made up a down quark and an up antiquark. a meson consists of a particle and an antiparticle, so it is very unstable.

  28. Leptons six leptons; three have electrical charge and three do not. The three charged leptons are theelectron (e-), muon() and the tau(), Three types of neutrinos (). They have no electrical charge, very little mass, and are hard to find. For each lepton there is a corresponding antimatter antilepton. anti-electron = the "positron.”

  29. Leptons Quarks are sociable; only exist in composite particles with other quarks leptons are solitary particles. charged leptons as independent cats with associated neutrino fleas, which are hard to see.

  30. Do Now (4/24/12): U-238 has a half-life of 4.46x109 years. How much U-238 should be present in a sample 2.5 x10 10 years old, if 2 grams were present initially?

More Related