Chapter3_Fall11

# Chapter3_Fall11 - 9/24/2011 Quantum Theory and the...

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9/24/2011 1 Quantum Theory and the Electronic Structure of Atoms Quantum Theory and the Electronic Structure of Atoms 3 3.1 Energy and Energy Changes 3.2 The Nature of Light 3.3 Quantum Theory 3.4 Bohr’s Theory of the Hydrogen Atom 35 Wave Properties of Matter 3.5 Wave Properties of Matter 3.6 Quantum Mechanics 3.7 Quantum Numbers 3.8 Atomic Orbitals 3.9 Electron Configuration 3.10 Electron Configurations and the Periodic Table Energy and Energy Changes Energy is the capacity to do work or transfer heat. The SI unit is Joule (J) , but chemists often use kJ or calories . 1 J = 1 kg m 2 /s 2 1 cal=4.184 J (exactly) 1 ca is defined to be the energy required to raise the temperature of 1 g 1 cal is defined to be the energy required to raise the temperature of 1 g of water by 1 o C. Types of Energy Kinetic (E k ) – energy resulting from motion Potential - energy possessed by an object by virtue of its position. Kinetic Energy The energy associated with motion Thermal energy is a form of kinetic energy, it arises from motion of atoms and molecules. Potential Energy Chemical energy is energy stored within the structural units of chemical substances. Electrostatic energy is potential energy that results from the interaction of charged particles. Law of conservation of energy Energy can neither be created nor destroyed. Kinetic and potential energy are interconvertible – one can be converted to the other. Energy is transferred through heat and work Stirling engine - how does this work?

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9/24/2011 2 The nature of light Wave–Particle Duality An electromagnetic wave has both an electric field component and a magnetic component. The electric and magnetic components have the same frequency and wavelength. Wavelength ( λ ; lambda ) – the distance between identical points on successive waves Frequency ( ; nu) – the number of waves that pass through a particular point in 1 second. Amplitude the vertical distance Properties of Waves – the vertical distance from the midline of a wave to the top of the peak or the bottom of the trough. The speed of light (c) through a vacuum is a constant: c = 2.99792458×10 8 m/s rounded to 3.00×10 8 m/s. Electromagnetic Radiation Energy Wavelength determines Energy Longer Wavelength – Lower Energy h= 6.626 × 10 -34 J·s h Planck’s constant When light passes through two closely spaced slits, an interference pattern is produced. Diffraction Constructive interference is a result of adding waves that are in phase. Destructive interference is a result of adding waves that are out of phase. This type of interference is typical of waves and demonstrates the wave nature of light. Electromagnetic Radiation Summary A photon is a form of radiant energy that travels at the speed of light and that can have a particular frequency ( ) and wavelength ( )t h a t determines its energy Photons travel at the speed of light (c), which is, in a vacuum: c=3.0 x 108 m/s Frequency in s -1 and wav length ) in m are related to the speed o Frequency ( ) in s
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## This note was uploaded on 02/20/2012 for the course 160 161 taught by Professor Kim during the Fall '08 term at Rutgers.

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Chapter3_Fall11 - 9/24/2011 Quantum Theory and the...

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