MKTG 477 1st EditionLecture 10Outline of Last LectureI. Atoms, Ions and Moleculesa. Big Bang TheoryOutline of Current LectureII. Atomic Structure: explaining the properties of elementsa. Wave theoryb. Atomic spectrac. Quantum theory Current lecture:Definition: Electromagnetic spectrum = _a continuous (no gas) range of radiant energy (electromagnetic radiation) _______ that includes gamma rays, X-Rays, ultraviolet radiation, visible light, infrared radiation, and radio waves. V x _ = cl = the wavelength (in __m, cm, nm n = the frequency (in __Hertz (hv) = s^-1__) c = the speed of light in vacuum (in _m/s__) c = 2.99792458 × 108 m/s Definitions: German physicist Joseph von Fraunhofer (1787-1826) Fraunhofer lines (dark line spectra) = a set of dark lines____ in the otherwise continuous solar spectrum. 3.2 atomic spectra Atomic absorption spectra = characteristic patterns of _dark lines_ produced when an external source of radiation passes through free, gaseous atoms. Atomic emission spectra = characteristic patterns of _bright lines produced when atoms are vaporized in high-temperature flames or electrical Discharges. Atomic emission spectra of gaseous elements in gas-discharge tubesAtomic absorption spectra of gaseous elements illuminated by Atomic emission spectra → Bright lines ___ Atomic absorption spectra → _dark lines _ Obs: For any given element, _the dark lines _in its absorption spectrum are at exactly the same wavelengths as __the bright lines in its emission spectrum. 3.3 Particles of Light: Quantum Theory Wave Theory Definition: Blackbody radiators = bodies that absorbs _all the light that strikes them (perfect absorbers) _ Obs: -The __wave theory_• could not explain these spectra. -Most intense emissions are in the infrared region. -There are little or no emissions in UV. Quantum Theory - German physicist Max Planck (1858-1947)Definitions:Quantum theory = a model based on the idea that energy is absorbed and emitted in _discrete quantities of energy called quanta. Quantum (plural quanta) = _the smallest discrete quantity__of a particular form of energy. Radiant energy is _quantized (have value) __ = having values restricted to whole-number multiples of a specific base value. Photon = ___a quantum of electromagneticradiation _ • Energy of photon: (E= h x v = h x c/ • h = 6.626 × 10-34 J•s (Planck’s constant) Obs: -Quantized states have _discrete energy levels (e.g., stairs) -Continuum states haveA smooth transition b/t levels (e.g., ramp) _ Definition: Photoelectric effect = the release of _electrons__ from a material as a result of_electromagnetic radiation striking it. Obs: Photoelectrons are emitted when the frequency of the incident radiation is _above some minimum pressure value__. Obs: The photoelectric effect is explained by _quantum theory___• Photons of sufficient energy (hn) dislodge electrons from the metal surface. Definitions: Threshold frequency (no) = the minimum frequency of light required to _produce the photo electric effect_. Work function (F) = the amount of energy needed to _dislodge an electron from the surface of a material. F = work function no = threshold frequency Kinetic energy of photoelectrons: KE= hv-