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Nuclear Energy

Nuclear Energy. Atoms and Radioactivity. Atoms and Radioactivity. Atoms – all common matter is made up of atoms. Three parts to an atom:. protons,. electrons , and. neutrons. Protons and neutrons occur together in the middle of the atom. Middle is called the nucleus.

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Nuclear Energy

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  1. Nuclear Energy Atoms and Radioactivity

  2. Atoms and Radioactivity • Atoms – all common matter is made up of atoms • Three parts to an atom: • protons, • electrons, and • neutrons • Protonsand neutrons occur together in the middle of the atom • Middle is called the nucleus • Nearly all the massof an atom is in the nucleus • Nucleus is orbited by the electrons of the atom

  3. Atoms and Radioactivity • Atoms that are electrically neutral contain the same number of protons and electrons • proton • electron • neutron • nucleus

  4. Atoms • The basic properties of an atom are determined by the number of protonsin its nucleus • All atoms of the same element have the samenumber of protons in their nuclei • The number of protons in an atom is called the atomicnumber of the element • proton • Oxygen has 8 protons: • atomic number is 8 • Uranium has 92 protons: • atomic number is 92 • nucleus

  5. Atoms • The atoms of most elements, have neutrons as well as protons and electrons • The number of protons plusthe number of neutrons in an atom is referred to as the mass number • Electrons are not counted in determining mass • proton • neutron • Because electrons have so little mass as compared to protons and neutrons • Atomic Number: • 2 • Atomic Mass: • 4 • Helium Atom • nucleus

  6. Element Song

  7. Periodic Table • Examples • atomicnumber: • number of protons • A • Symbol of the element • atomicmass: • number of protons and neutrons • How many protons does carbon have? • 6 • 12 • – 6 • = 6 • How many neutrons does carbon have?

  8. Periodic Table • Examples • B. Which element has 30 protons? • Zinc • How many neutrons does it have? • 65 • – 30 • neutrons • = 35 • C. Which element has 47 protons? • Silver • How many neutrons does it have? • 108 • – 47 • = 61 • neutrons

  9. Isotopes • Isotopes: Atoms of the same element that have different numbers of neutrons • Individual atoms of the same element may have different mass numbers • Because the number of neutrons in the nucleus can vary • Always have the same number of protons

  10. Isotopes • Example: All oxygen atomshave 8 protons • 8 • Most oxygen atoms have __ neutrons • However, some oxygen atoms may have 9 or 10 neutrons • These oxygen atoms are isotopes • They have the same atomic number • They have different atomic masses Atomic Number: Atomic Number: 8 8 Atomic Mass: Atomic Mass: 16 18

  11. Radioactivity • Some isotopes of atoms are unstable • Unstable atoms decay, emitting particles and energy from their nuclei • Atoms that decay in this way are called radioactiveatoms • In most cases, only certain isotopes of an element are radioactive. • Example: Common isotopes of Hydrogen • H-1 is not radioactive, • H-2 is not radioactive, • H-3 is radioactive • After a series of decay changes, a radioactive element becomes stable and stops decaying

  12. Radiation • Radiation – the particles or energy given off as an atom decays • There are two kinds of particles given off by the nuclei of radioactive atoms • Alpha Particles (α) – made up of two protons and two neutrons

  13. Radiation • Beta Particles (β) – release of a high speed electron • Beta decay converts a neutronintoaproton • When atoms emit alpha or beta particles, it changes the number of protons – which changes atomic number • It also changes the atomic mass of the atoms

  14. Radiation • Since the atomic number of an atom determines the identity of the element, the decay process changes one element into another element • The third type of radiation is when energy in the form of GammaRays is given off • Gamma rays are a form of electromagnetic radiation • Types of radioactive decay video

  15. Half-Life • Two radioactive isotopes of uranium are U-238 (over 99 percent of all uranium found in nature) and U-235 • The amount of time it takes for half of the atoms in a sample of a radioactive element to decay is called the isotope's half-life • Half-lives for various radioactive elements range from a few seconds to billions of years • Both ultimately decay into stable forms of lead • But the process takes a long time • U-238 half-life is about 4.5 billion years • U-235 half-life is about 700 million years

  16. Section Review • Answer the questions in the section review

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