Chpt 5.pdf - Chapter 5 Periodicity and the Electronic...

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9/15/20191Chapter 5Periodicity and the Electronic Structure of AtomsCHEM 1211K1Periodicity and the Electronic Structure of Atoms2The color emitted by elements heated in a flame arises from electrons moving between different energy levels in an atom.Atoms emit characteristic colors because each has its own unique energy levels.How does knowledge of atomic emission spectra help us build more efficient light bulbs? Learn more at the end of the chapter.Unnumbered figure, page 15412
9/15/20192The Nature of Radiant Energy and the Electromagnetic SpectrumLight is a form of , which consists of oscillating (time-varying) electric and magnetic fields.All forms of electromagnetic radiation transfer energy from one region of space to another.3The Nature of Radiant Energy and the Electromagnetic SpectrumImportant attributes of light:434
9/15/20193The Nature of Radiant Energy and the Electromagnetic SpectrumFrequencyis the number of cycles of a wave per second.Measured in Hertz (Hz)5The Nature of Radiant Energy and the Electromagnetic SpectrumThe color of light (visible spectrum) depends on its wavelengthand frequency656
9/15/20194Particle Like Properties of Radiant Energy: The Photoelectric Effect and Planck’s PostulateMax Planckproposed that the exchange of energy between matter and radiation occurs in _______or packets of energy. Experimental evidence this theory was provided by the ____________________ .7Particle Like Properties of Radiant Energy: The Photoelectric Effect and Planck’s Postulate878
9/15/20195Particle Like Properties of Radiant Energy: The Photoelectric Effect and Planck’s PostulateAlbert Einstein explained the photoelectric effect.Electromagnetic radiation consists of particles called .9Particle Like Properties of Radiant Energy: The Photoelectric Effect and Planck’s PostulateExample:What is the energy of a single photon of blue light of frequency 6.4 x 1014Hz? What is the energy of a mole of photons of the same frequency?10910
9/15/20196The Interaction of Radiant Energy with Atoms: Line Spectra_________ consists of essentially continuous distribution of wavelengths spanning the entire visible region of the electromagnetic spectrum. Atoms give off light when heated or otherwise energetically excited. 11The Interaction of Radiant Energy with Atoms: Line Spectra12Light from a hydrogen discharge tube is passed through a narrow slit and then a prism.1112
9/15/20197The Interaction of Radiant Energy with Atoms: Line SpectraPassing white light through a vapor composed of the atoms of an element produces an absorption spectrum.13Atkins’ 6thed.The Bohr Model of the Atom: Quantized EnergyNiels Bohr – proposed a hydrogen atomic model that was used to predict the existence of line spectra.

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