© Copyright Pearson Prentice Hall Slide 1 of 21 Nuclear Radiation Marie Curie was a Polish scientist whose research led to many discoveries about radiation and radioactive elements. In 1934 she died from leukemia caused by her long-term exposure to radiation. You will learn about the various types of radiation and their effects. 25.1

© Copyright Pearson Prentice Hall Nuclear Radiation > Slide 2 of 21 Radioactivity How does an unstable nucleus release energy? 25.1

Slide 3 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Radioactivity Marie Curie ( ) and Pierre Curie ( ) were able to show that rays emitted by uranium atoms caused fogging in photographic plates. Marie Curie named the process by which materials give off such rays radioactivity. The penetrating rays and particles emitted by a radioactive source are called radiation. -They discovered several radioactive isotopes. *reason that Dalton’s indivisible atom idea was changed 25.1

Slide 4 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Radioactivity Nuclear reactions differ from chemical reactions in a number of important ways. In chemical reactions, atoms tend to attain stable electron configurations by losing or sharing electrons. In nuclear reactions, the nuclei of unstable isotopes, called radioisotopes, gain stability by undergoing changes, and are ALWAYS accompanied by emission of large amounts of energy. 25.1

© Copyright Pearson Prentice Hall Slide 5 of 21 Nuclear Radiation > Radioactivity An unstable nucleus releases energy by emitting radiation during the process of radioactive decay. An unstable nucleus is something that is considered to have either too few neutrons or too many neutrons relative to the number of protons. Eventually unstable radioisotopes transform into stable isotopes of a different element. 25.1

© Copyright Pearson Prentice Hall Nuclear Radiation > Slide 6 of 21 Types of Radiation What are the three main types of nuclear radiation? 25.1

Slide 7 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation The three main types of nuclear radiation are alpha radiation, beta radiation, and gamma radiation. 25.1

Slide 8 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation Alpha Radiation Alpha radiation consists of helium nuclei that have been emitted from a radioactive source. These emitted particles, called alpha particles, (α) contain two protons and two neutrons and have a double positive charge. 25.1

Slide 9 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation Beta Radiation An electron resulting from the breaking apart of a neutron in an atom is called a beta particle. (β) 25.1

Slide 10 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation Carbon-14 emits a beta particle as it undergoes radioactive decay to form nitrogen

Slide 11 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation 25.1

Slide 12 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation 25.1

Slide 13 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation Gamma Radiation A high-energy photon emitted by a radioisotope is called a gamma ray. ( ϒ ) The high-energy photons are electromagnetic radiation. 25.1

Slide 14 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation Alpha particles are the least penetrating. Gamma rays are the most penetrating. 25.1

Slide 15 of 21 © Copyright Pearson Prentice Hall Nuclear Radiation > Types of Radiation 25.1

© Copyright Pearson Prentice Hall Slide 16 of 21 Section Quiz -or- Continue to: Launch: Assess students’ understanding of the concepts in Section 25.1 Section Quiz

© Copyright Pearson Prentice Hall Slide 17 of Section Quiz. 1.Certain elements are radioactive because their atoms have a.more neutrons than electrons. b.an unstable nucleus. c.a large nucleus. d.more neutrons than protons.

© Copyright Pearson Prentice Hall Slide 18 of Section Quiz. 2.An unstable nucleus releases energy by a.emitting radiation. b.thermal vibrations. c.a chemical reaction. d.giving off heat.

© Copyright Pearson Prentice Hall Slide 19 of Section Quiz. 3.Which property does NOT describe an alpha particle? a.2+ charge b.a relatively large mass c.a negative charge d.low penetrating power

© Copyright Pearson Prentice Hall Slide 20 of Section Quiz. 4.When a radioactive nucleus releases a high- speed electron, the process can be described as a.oxidation. b.alpha emission. c.beta emission. d.gamma radiation.

© Copyright Pearson Prentice Hall Slide 21 of Section Quiz. 3.Which property does NOT describe an alpha particle? a.2+ charge b.a relatively large mass c.a negative charge d.low penetrating power