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Nuclear Energy Nuclear Structure and Radioactivity I. Review - Periodic Table A. Atomic Number: • B. The number of protons in the nucleus of an atom Atomic Mass: • The sum of the mass of protons, neutrons and electrons in the atom • # of neutrons = atomic mass - atomic number Il. Review - Atomic Structure Recognize Me? A. Atomic Structure: • B. Atoms contain protons, neutrons and electrons Isotopes: • The number of neutrons in an atom is not always the same! • Atoms of the same elements that have an abnormal number of neutrons are called Isotopes. III. Radioactivity A. Definition: The emission of radiation due to the breakdown of atomic nuclei B. Description of Process: • Isotopes and large atoms are unstable and will break apart • New, lighter atoms are formed, releasing radiation in the process • Unstable atoms will continue to break down until they become stable IV. Radiation A. Definition: Energy that is radiated or transmitted in the form of rays, waves or particles B. Types of Radiation 1. Alpha () Particle : • Nucleus of a helium atom; Charge (+2); Mass of 4 • Alpha decay occurs because the nucleus has too many protons which causes excessive repulsion. An alpha particle is emitted to reduce this. • The atomic # of the decaying atom decreases by 2 and the mass decreases by 4 Symbol IV. Radiation B. Types of Radiation 2. Beta ( Particle : • High speed electron • Charge (-1); No measurable mass • Beta decay occurs when the neutron to proton ratio is too great and causes instability. A beta particle is emitted, converting a neutron into a proton. • The atomic # of the decaying atom increases by 1and the mass does not change Symbol IV. Radiation B. Types of Radiation 3. Gamma ( ) Ray : • High energy photon (wave) • No charge; No measurable mass • Gamma decay occurs because the nucleus is at too high an energy. A gamma ray is emitted as the nucleus falls to a lower energy state. • The atomic number and mass of the decaying atom do not change Symbol Radiation Summary Slide V. Energy Generated From Nuclear Fission A. Definition: The splitting of large atomic nuclei into smaller fragments B. Description of Process: • A large atom is struck by a single neutron • Fission products include smaller atoms, neutrons and heat energy • Uranium-235 is the most common isotope used to generate useable nuclear energy in power plants VI. Energy Generated From Nuclear Fusion A. Definition: The combining of small atomic nuclei to form larger ones B. Description of Process: • The mass of the combination is less than the sum of the masses of the individual nuclei. Mass is converted into energy! • Takes place continuously in the sun and stars (H is converted into He) • For energy production on earth, the nuclei of two isotopes of hydrogen are used: Deuterium and Tritium C. Energy Released from Nuclear Fusion: • 10 grams of Deuterium which can be extracted from 500 liters of water could produce enough fuel for the lifetime electricity needs of an average person in an industrialized country. • Do we use fusion to generate electricity?