Topic 7 Ib Physics Sl

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  • Topic: Neutron, Atom, Atomic nucleus
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  • Published : August 29, 2012
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Assessment Statement | | Definition |
Topic 7: Atomic and Nuclear Physics |
7.1.1. Describe a model of the atom that features a small nucleus surrounded by electrons. | | Rutherford Model: a dense positive nucleus is orbited by negatively charged electrons due to the electrostatic attraction between them. | 7.1.2. Outline the evidence that supports the nuclear model of an atom. | | Rutherford (Geiger- Marsden) emperiment -An experiment in which alpha particles were directed at a thin foil of gold. Most went through only slightly deflected but a few were turned back, indicating the existence of a tiny, massive, positive charge inside of the atom: the atomic nucleus. | 7.1.3. Outline one limitation of the simple model of the nuclear atom. | | -Why were electrons not drawn to the nucleus? -How is nucleus composed? -Why weren't protons repelled from each other when electrostatic forces are taken into account? | 7.1.4. Outline evidence for the existence of atomic energy levels | | -Light is emitted in specific colors when elements are heated (energy added) -Line/emission spectrum: the spectrum of frequencies of electromagnetic radiation emitted when the electrons return to a lower energy state. Series of bright lines, dark gaps between lines where no light is emitted. -Absorption spectrum: spectrum with dark bands where an element absorbs light -Spectroscopy: study of these spectra | 7.1.5. Explain the terms nuclide, isotope, and nucleon. | | Nuclide: a nucleus with a specific number of protons and neutrons Isotopes: Nuclei with the same atomic number but different mass number (due to a different number of neutrons) Nucleon: a proton or a neutron making up a nucleus | 7.1.6. Define nucleon number A, proton number Z and neutron number N. | | Z: atomic or proton number. Also shows electric charge of nucleus. Units |e| A: Total number nucleons (protons+neutrons). Called...
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