Section 1: Nuclear Radiation Under certain conditions, some nuclei can emit alpha, beta, or gamma radiation. K What I Know W What I Want to Find Out L What I Learned

12(A) Describe the characteristics of alpha, beta, and gamma radiation. 3(F) Research and describe the history of chemistry and contributions of scientists. Copyright © McGraw-Hill Education Nuclear Radiation

Essential Questions How was radioactivity discovered and studied? What are the key properties of alpha, beta, and gamma radiations? Copyright © McGraw-Hill Education Nuclear Radiation

Vocabulary Review New nucleus radioisotope X-ray penetrating power Nuclear Radiation Copyright © McGraw-Hill Education

The Discovery of Radiation Nuclear chemistry is concerned with the structure of atomic nuclei and the changes they undergo. Nuclear reactions are different from other types of reactions. Marie Curie and her husband Pierre isolated the first radioactive materials. Table 1 Comparison of Chemical and Nuclear Reactions Chemical Reactions Nuclear Reactions Occur when bonds are broken and formed Involve only valence electrons Associated with small energy changes Atoms keep the same identity although they might gain, lose, or share electrons, and form new substances Temperature, pressure, concentration, and catalysts affect reaction rates Occur when nuclei combine, split, and emit radiation Can involve protons, neutrons, and electrons Associated with large energy changes Atoms of one element are often converted into atoms of another element Temperature, pressure, and catalysts do not normally affect reaction rates Nuclear Radiation Copyright © McGraw-Hill Education

Types of Radiation Isotopes of atoms with unstable nuclei are called radioisotopes. Unstable nuclei emit radiation to attain more stable atomic configurations in a process called radioactive decay. The three most common types of radiation are alpha, beta, and gamma. Copyright © McGraw-Hill Education Nuclear Radiation

Types of Radiation Alpha particles have the same composition as a helium nucleus—two protons and two neutrons. Because of the protons, alpha particles have a 2+ charge. Alpha radiation consists of a stream of particles. Alpha radiation is not very penetrating—a single sheet of paper will stop an alpha particle. Copyright © McGraw-Hill Education Nuclear Radiation

Types of Radiation Beta particles are very fast-moving electrons emitted when a neutron is converted to a proton. Beta particles have insignificant mass and a 1– charge. Beta radiation is a stream of fast moving particles with greater penetrating power—a thin sheet of foil will stop them. Copyright © McGraw-Hill Education Nuclear Radiation

Types of Radiation Gamma rays are high-energy electromagnetic radiation. Gamma rays have no mass or charge. Gamma rays almost always accompany alpha and beta radiation. X rays are a form of high-energy electromagnetic radiation emitted from certain materials in an excited state. The ability of radiation to pass through matter is called its penetrating power. Gamma rays are highly penetrating because they have no charge and no mass. Copyright © McGraw-Hill Education Nuclear Radiation

Review Essential Questions Vocabulary How was radioactivity discovered and studied? What are the key properties of alpha, beta, and gamma radiations? Vocabulary radioisotope X-ray penetrating power Nuclear Radiation Copyright © McGraw-Hill Education