1 / 19

Chapter 25 Nuclear Chemistry

Chapter 25 Nuclear Chemistry. 25.1 Nuclear Radiation. Chemistry. Today we are learning to:- 1. Understand about early discoveries on radioactivity 2. See how an unstable nucleus can release energy 3. Describe 3 types of radiation. Nuclear Radiation. Radioactivity.

graham-mcneil
Download Presentation

Chapter 25 Nuclear Chemistry

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. Chapter 25 Nuclear Chemistry 25.1 Nuclear Radiation

  2. Chemistry • Today we are learning to:-1. Understand about early discoveries on radioactivity2. See how an unstable nucleus can release energy • 3. Describe 3 types of radiation

  3. Nuclear Radiation Radioactivity • Born on November 7, 1867, in Warsaw, Poland, Marie Curie became the first woman to win a Nobel Prize and the only woman to win the award in two different fields (physics and chemistry). Curie's efforts, with her husband, Pierre, led to the discovery of polonium and radium and, after Pierre's death, the development of X-rays. She died on July 4, 1934. http://www.biography.com/people/marie-curie-9263538 Marie-Curie-Biography

  4. Nuclear Radiation Radioactivity • In 1896, Antione Becquerel (French) accidentally showed that uranium salts would fog a photographic plate. • The Curies demonstrated that the fogging was caused by rays emitted by the uranium • They called this process radioactivity, and the rays and particles are called radiation

  5. Nuclear Radiation Radioactivity • Nuclear reactions differ from chemical reactions in important ways: • In chemical reactions, atoms obtain stable electron configurations by losing, gaining or sharing electrons. • In nuclear reactions, the nuclei of unstable isotopes, called radioisotopes, gain stability by undergoing changes. • The discovery of radioactivity disproves Daltons assumption of indivisible atoms • In radioactive decay unstable radioisotopes are transformed into stable isotopes releasing large amounts of energy as radiation

  6. Nuclear Radiation Types of Radiation • 3 Main types: • Alpha radiation(α – radiation) • Beta radiation (β – radiation) • Gamma radiation (γ – radiation)

  7. Nuclear Radiation Types of Radiation • Alpha radiation(α – radiation) • Consists of alpha particles(α – particles) • These are high energy helium nuclei which are ejected from a radioisotope at high velocity ( or α) • When an α – particle is emitted: • the atomic number of the nucleus falls by 2 • the mass number of the nucleus falls by 4

  8. Nuclear Radiation Types of Radiation • Beta radiation(β– radiation) • Consists of beta particles(β – particles) • These are high energy electrons which are ejected from a radioisotope at high velocity ( or β) • When a β – particle is emitted: • A neutron breaks apart to form a proton and an electron • the atomic number of the nucleus increases by 1 • the mass number of the nucleus stays the same

  9. Nuclear Radiation Types of Radiation • Gamma radiation(γ – radiation) • Consists of very high energy photons (γ – rays) • This electromagnetic radiation is often emitted from the nucleus at the same time as α or β radiation • γ – rays: • Have zero mass • Travel at the speed of light • Do not affect atomic number or mass number

  10. Nuclear Radiation Effect of an Electric Field Look at the diagram. Write in your notebooks what you can tell about the effect of an electric field on each type of radiation. Write down what you think may be the reason for the differences in their deflections

  11. Nuclear Radiation Penetrating Power Look at the diagram. Write in your notebooks what you can see about the penetrating power of each type of radiation. Write down what you think may be the reason for the differences in penetrating power

  12. 25.1 Types of Radiation Homework questions: Answer Questions 25-32 on page 821 of your text book for next day (use a periodic table to help identify products.)

  13. 25.1 Section Quiz. 1. Certain elements are radioactive because their atoms have • more neutrons than electrons. • an unstable nucleus. • a large nucleus. • more neutrons than protons.

  14. 25.1 Section Quiz. 2. An unstable nucleus releases energy by • emitting radiation. • thermal vibrations. • a chemical reaction. • giving off heat.

  15. 25.1 Section Quiz. 3. Which property does NOT describe an alpha particle? • 2+ charge • a relatively large mass • a negative charge • low penetrating power

  16. 25.1 Section Quiz. 4. When a radioactive nucleus releases a high-speed electron, the process can be described as • oxidation. • alpha emission. • beta emission. • gamma radiation.

  17. 2.3 Vocabulary 25.1 Vocabulary • Radioactivity:process where materials give off high energy rays • Radiation:name give to these penetrating rays and particles • Radioisotopes: unstable isotopes that will decay into a different element • Alpha particle: high energy helium nuclei containing 2 protons and 2 neutrons • beta particle: high energy electron emitted from a nucleus • Gamma particle: high energy electromagnetic radiation emitted from a nucleus

  18. END OF SHOW

More Related