Notes- ch 3
Notes- ch 3 CHEM 1030 - 003
Popular in Fundamentals Chemistry I
Popular in Chemistry
This 8 page Class Notes was uploaded by Karlee Castleberry on Friday September 18, 2015. The Class Notes belongs to CHEM 1030 - 003 at Auburn University taught by John D Gorden in Fall 2015. Since its upload, it has received 107 views. For similar materials see Fundamentals Chemistry I in Chemistry at Auburn University.
Reviews for Notes- ch 3
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/18/15
Tuesday September 8 2015 Chapter 3 32 Nature of Light visible light is only a small component of continuum of radiant energy known as the electromagnetic spectrum speed of light 0 through a vacuum is a constant c 300 x 108 speed of light frequency and wavelength are related c wavelength lambda metersfrequency s1 aka hertz properties of waves all forms of electromagnetic radiation travel in waves frequency number of waves per second wavelength length of 2 identical points on wave amplitude vertical distance from midline to peak bottom of wave intensity of light electromagnetic wave both electric field light and magnetic mass matter doubleslit experiment when light passes through two closely spaced slits an interference pattern is produced constructive interference wavelength in line with other wavelength destructive interference wavelength out of line with other wavelength Tuesday September 8 2015 33 Quantum Theory Quantization of Energy when solid headed emits electromagnetic radiation called blackbody radiation over a wide range of wavelengths amount of energy given off at a certain temp depends on the wavelength radiation is continuous could be emitted or absorbed at any amount quantum smallest quantity of energy that can be emitted or absorbed energy of a single quantum of energy is E hv h is Planks constant 663 x 1034 J s E hcA protons and the photoelectric effect used planck s theory to explain photoelectric effect electrons ejected from surface of a metal exposed to light of certain minimum frequency called threshold frequency number of photons ejected dependent upon intensity of the light high frequency high energy low wavelength high energy hv KE W quotIight quotmatter easier it is to remove electron smaller number will be high work function higher number more reactive smaller work function W is binding energy of electron Tuesday September 8 2015 Thursday September 10 2015 34 Bohr s Theory of the Hydrogen Atom emission spectrum seen by energizing sample of material with energy emission of sunlight and heated solid are continuous all wavelengths of visible light present atomic line spectra line spectra emission of light only at specific wavelengths ultraviolet purple more energy closer to red less energy every element has its own unique emission spectrum this light wavelength means this has this element in it Rydberg equation is used to calculate the wavelengths of the four visible lines in the emission spectrum of hydrogen 1A Rinfinity 1n1quot2 1n2 A2 R is the Rydberg constant 1 09737317 x 107 m4 A the wavelength of a line in the spectrum m and n2 are positive integers where n2 gt m line spectrum of hydrogen Bohr showed that energies of the electron in a hydrogen atom are given by the equa on En 218 x1018 J 1n2 En is the energy n is a positive integer En becomes larger in absolute value but more negative as n gets smaller it is almost negative when n1 called ground state the lowest energy state of the atom for hydrogen this is the most stable state the stability of the electron decreases as n increases Thursday September 10 2015 each energy state in which n gt 1 is called an excited state hydrogen 1 lithium 2 ect for its outermost electron Bohr s theory radiant energy absorbed by the atom causes the electron to move from the ground state n 1 to an excited state n gt 1 radiant energy is emitted when the electron moves from a higherenergy state to a lowerenergy excited state or the ground state nl initial state nf is the final state a photon is emitted when n gt hi AE is negative a photon is absorbed when nr gt hi AE positive the energy diff between the final and initial states is AE hv 218 X 103918 J 1an2 1niquot2 to calculate wavelenth substitute clambda for v and rearrange 1A 218 x1OA18 Jhc x 1nf quot2 1niquot2 be able to predict how many different lines are possible every possible option gives you a different wavelength Thursday September 10 2015 35 Wave Properties of Matter According to de Broglie electrons behave like standing waves at a node the amplitude of the wave is zero particle and wave properties are related by lambda hmu lambda is the wavelength associated with the particle m is the mass in kg u is the velocity in ms the wavelength calculated from this equation is known as the de broglie wavelength The Schrodinger Equation and The Quantum Mechanical Description of the Hydrogen Atom derived math formula to incorporate wave and particle characteristics of electrons wave behavior is described with the wave function LJ the probability of finding an electron in a certain area of space is proportional to LJ2 and is called electron density quantum mechanics defines the region where the electron is most likely to be at a given time the schrodinger equation specifies possible energy states an electron can occupy in a hydrogen atom the energy states and wave functions are characterized by a set of quantum numbers instead of referring to orbits as in the Bohr model quantum numbers and wave functions describe atomic orbitals quantum numbers are required to describe the distribution of electron density in an atom there are 3 quantum numbers necessary to describe an atomic orbital principle quantum number n designates size Thursday September 10 2015 always whole number angular moment quantum number I describes shape O 1 2 3 spdf always a whole number if n is one is 0 only ifn2lcanbe10 ifn3lcanbe210 5 region 2 molecules p region 6 molecules d region 10 molecules magnetic quantum number m specifies orientation review table 32 in book ml l1 l2 l3 until you get to negative I mS spin of electron either l2 or 12 39 2px 2 principle n2 p angular momentum l1 x magnetic quantum number x y or z 38 atomic orbitals all s orbitals are spherical but differ in size has 0 nodes 1sO2s13s2 a p orbitaland has 1 node 2p orbital 1 3p 2 Thursday September 10 2015 a d orbital has 2 nodes 39 Electron Configurations electron configuration describes how electrons are distributed in the various atomic orbitals in a ground state hydrogen atom the electron is found in the 1s orbital
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'