When controlled, nuclear energy has many practical uses… CHAPTER 10 Nuclear Chemistry When controlled, nuclear energy has many practical uses… This submarine is powered by a fission reaction that releases large amounts of energy

10.1 Radioactivity Key Concepts What happens during nuclear decay? What are three types of nuclear radiation? How does nuclear radiation affect atoms? What devices can detect nuclear radiation?

The image was caused by __________ that had not been observed before. When Henri ____________ placed uranium salts on a photographic plate and then developed the plate, he found a __________ image. The image was caused by __________ that had not been observed before. He shared the 1903 Nobel Prize for Physics with Marie and Pierre ___________. Becquerel foggy rays Curie

Nuclear Decay Radioactivity is the process in which an ______________ atomic nucleus emits charged particles and energy. Any atom containing an unstable nucleus is called a radioactive isotope, or _________________ for short. During nuclear decay, atoms of one element can change into atoms of a ______________ element altogether. different unstable radioisotope

Types of Nuclear Radiation Scientists can detect a radioactive substance by measuring the nuclear radiation it gives off. Nuclear radiation is charged _______________ and _________________ that are emitted from the nuclei of radioisotopes. What does the word emitted mean? particles energy given off / released

Types of Nuclear Radiation

Types of Nuclear Radiation Alpha Decay An alpha particle is a ________________ charged particle made up of two protons and two neutrons—the same as a ____________ nucleus. When a uranium-238 sample decays, it emits alpha particles. An alpha particle has a 2+ charge An alpha particle has a mass of 4 amu. The symbol for an alpha particle, ______, shows its mass and charge. positively helium 4 2 He

Types of Nuclear Radiation The nuclear equation for the alpha decay of uranium-238 is shown below. The mass number on the left (238) ____________ the sum of the mass numbers on the right (____________). The atomic number on the left (92) equals the sum of the atomic numbers on the right (___________). The equation is ________________. = equals 238 92 balanced

Types of Nuclear Radiation A beta particle is an ______________ emitted by an unstable nucleus. The symbol for a beta particle is _______. During beta decay, a neutron decomposes into a proton and an electron. The proton stays trapped in the nucleus, while the electron is released. A beta particle is assigned an atomic # of ______. A beta particle is assigned a mass number of ____. electron -1 e -1

Types of Nuclear Radiation The balanced equation for beta decay of thorium-234 is shown below. =

Types of Nuclear Radiation Gamma Decay A gamma ray is a penetrating ray of __________ emitted by an unstable nucleus. Gamma radiation has ____ mass and ____charge. Like X-rays and visible light, gamma rays are energy waves that travel through __________ at the speed of light. energy no no space

Types of Nuclear Radiation Gamma radiation also involves balanced equations, but the energy of the nucleus __________________. decreases energy emitted

Types of Nuclear Radiation The penetrating power of nuclear radiation varies with the type.

Types of Nuclear Radiation Balancing Nuclear Equations Write a balanced nuclear equation for the alpha decay of polonium-210. 206 = Pb 82 Look up atomic # on P.T.

Write a balanced nuclear equation for the beta decay of carbon-14. = N 7 Look up atomic # on P.T.

Effects of Nuclear Radiation Background radiation is nuclear radiation that occurs _______________ in the environment. Radioisotopes in air, water, rocks, plants, and animals all contribute to background radiation. Cosmic rays are streams of charged particles (mainly protons and alpha particles) from outer space. Background radiation levels are generally ________ enough to be safe. naturally low

Effects of Nuclear Radiation When nuclear radiation exceeds background levels, it can ____________ the cells and tissues of your body. Nuclear radiation can ______________ atoms. It may break the bonds in your _________, affecting cell functions. damage ionize DNA

Effects of Nuclear Radiation __________ gas is produced underground as the uranium in rocks and soil decays. Radon Insulation, modern windows, and modern building materials keep radon from escaping. Radon gas dissolved in water is released through agitation. Radon naturally diffuses up through the ground. Radon enters through pinholes and cracks in the foundation. Radon is produced by the nuclear decay of uranium found in rocks and soil. Causes lung cancer

Detecting Nuclear Radiation A ______________ counter uses a gas-filled tube to measure ionizing radiation. When nuclear radiation enters the tube, it ionizes the atoms of the gas. The ions produce an electric ______________, which can be measured. Many people who work with or near radioactive materials wear _______________ to monitor their exposure to nuclear radiation. Geiger current film badges

What happens when an atomic nucleus decays? Assessment Questions What happens when an atomic nucleus decays? The atom loses an electron and gains energy. Some of the protons in the nucleus are converted to neutrons. A nucleus breaks into two parts of approximately equal mass. An unstable nucleus emits charged particles and energy.

During alpha decay, the nucleus emits an alpha particle, or Assessment Questions During alpha decay, the nucleus emits an alpha particle, or proton. neutron. deuterium nucleus. helium nucleus.

Assessment Questions Which isotope balances the nuclear equation for the alpha decay of thorium-232?

Nuclear radiation can damage cells in the body by Assessment Questions Nuclear radiation can damage cells in the body by ionizing atoms in molecules in the cell. making holes in the cell wall. making isotopes in the cell radioactive. causing water to vaporize and rupture the cell.

Assessment Questions 5. A Geiger counter measures radiation by detecting ions formed when charged particles pass through a tube filled with gas. True False