CHEM 1110 1st Edition Lecture 20Outline of Last Lecture I. Le Chatelier’s Principles and Equilibrium Outline of Current Lecture I. Wave and Particle Nature of Light II. Atomic Emission of Light (Spectra)III. Wave and Particle Nature of MatterIV. Quantum Mechanical Model of the Atom Current LectureI. Wave and Particle Nature of Light A. Periodic Properties and the Atom 1. Early chemist Observed that the properties of the elements were periodic- leading eventually to the periodic table (macroscopic observation)2. But why are the properties of the elements periodic (requires insight into microscopic behavior)3. The answer to this question was found in the quantum theory of the atoms electronic structure B. What is the Electronic Structure?1. The arrangement of electron in an atom includes a. The number of them in an atom b. Their distribution around the nucleus c. Their energies (absorption and radiation/emission)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.C. Electromagnetic Radiation- energy transmitted through space at the speed of light (in a vacuum) by waves having both electric and magnetic properties II. Wave Properties1. Wavelength: distance between peaks – a length2. Frequency: peak (wavelengths) passing a point in space per second B. Blackbody radiation 1. Matter emits radiation which changes in wavelength as the temperature increases2. Classical wave theory failed to explain observations at high or low wavelength C. Planck’s quantum theory1. Max Planck a. In 1900, he proposed that atoms emit or absorb energy only in small specific chunks or quanta b. Accurately predicted black body radiation emission c. Major outcomes i. Light comes in discrete units called quanta or photonsii. The energy in one light photon: E= hviii. Light can only have energies with integer multiples of hv iv. Plancks constant = h= 6.626x10-34D. Einstein’s photoelectric Effect1. Experimental verification of Planck’s quantum theory 2. A photon hits a metal surface and, if it has enough energy, it ejectsan electrons3. Ephoton>= metal’s work function= minimum E to release electron any extra phton enery becomes electron’s KE=1/2mv24. The light is transferring energy to the metal surface- where it is transformed into kinetic energy that give the electrons enough energy to leave the atoms in the metal 5. The moe intense (bright) the light, the more photons are added, and the more quickely electrons are ejected a. Kinetic energy of the electrons6. If light were a wave – increasing the intensity should always increase the energy E. Bohr Atomic Model1. Only certain orbital radii with discrete energies are allowed for electrons in atoms2. An electron in an allowed sate will not radiate energy 3. Energy is absorbed or emitted when an electron moves from one allowed state to another, All of the energy is absorbed or emitted in one photon of