Unit 9 Quantum


Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: QUANTUM THEORY AND MECHANICS MECHANICS Chapter 5 What is light? What ♦ Properties of light? ♦ Particles and Waves ♦ Light waves = electromagnetic waves ♦ Electromagnetic radiation ♦ Wave Characteristics: – Amplitude – Wavelength – Frequency – Speed Electromagnetic Radiation Radiation ♦ Increases in penetration, frequency, energy ♦ Decreases in wavelength Radio waves Microwaves IR Visible light Ultraviolet X-ray Gamma ROYGBIV Amplitude Amplitude ♦ The height of the wave measured from The the origin to its crest or peak. the ♦ Determines the brightness or intensity of Determines the light. the ♦ A measure of the maximum rise or fall of measure a wave. wave. ♦ Ψ = meters. Wavelength Wavelength ♦ The distance between successive crests of The the wave. the ♦ Includes one crest and one trough. ♦ Contains three consecutive nodes (crest Contains to crest or trough to trough). or ♦ λ = meters. Frequency Frequency ♦ Tells how fast a wave oscillates up and Tells down. down. ♦ Measured by the number of times a light Measured wave completes a cycle of upward and downward motion in one second. downward ♦ Repetitions or cycles per second. ♦ ν = 1/s = hertz = Hz. Velocity Velocity ♦ Light regardless of its wavelength moves Light at a constant speed. at ♦ Speed of light (c) = 3.00 x 108 m/s. ♦ Wavelength vs. Frequency: c=λxν or or λ=c/ν Quantum Theory Debate Quantum Wave Theory Rutherford-Bohr models of the atom starts the debate. ♦ Believe that the electron is only energy that Believe moves in the form of a wave. moves ♦ They set out to calculate the energy of each They orbit of Hydrogen from the work of Balmer. orbit ♦ Max Planck: “Planck’s Hypothesis” – Proposed “quanta” or small packages of energy. E=hxν ♦ Believe that the electron is only a particle that Believe Particle Theory Particle has mass and travels in a straight line. has ♦ They set out to calculate the energy of each They electron in the Hydrogen atom. electron ♦ Albert Einstein: “Relativity” E = mc2 ♦ Louie DeBroglie Duality Theory Duality ♦ Electron is both a particle and wave Electron (matter waves). (matter Wavelength = Planck’s constant Wavelength Planck’s momentum Quantum Mechanical Atom Quantum ♦ Erwin Schrodinger. ♦ Electron exists in a cloud in regions of Electron energy requirement based upon 2πr = λ. energy ♦ The highest probability of finding the The electron is closest to the nucleus. ♦ Heisenburg Uncertainty Principle – The position and momentum of a moving The object (electron) cannot be measured and known exactly. known Quantum Mechanics Quantum ♦ Electron density: the density of an Electron electron cloud. electron ♦ Atomic orbital: a region around the Atomic nucleus of an atom where an electron with a given energy is likely to be found. with ♦ Orbitals have characteristic shapes, sizes, Orbitals and energies. and ♦ S (spherical), p (dumbbell), d & f (more (spherical), complex). complex). Quantum Mechanics Quantum ♦ Principle energy level = n. ♦ The energy of the electron increases as n The increases. increases. ♦ Ground state vs excited state ♦ Sublevels: the number of sublevels in Sublevels: each principle level equals the quantum number (n). number – s, p, d, f. – 1s, 2s, 2p, 3s, 3p, 3d, etc. Quantum Mechanics Quantum ♦ Orbitals: each sublevel consists of one or more Orbitals: orbitals. orbitals. ♦ Electron’s “address”: consists of the principle Electron’s energy level, the sublevel, and its orbital within that sublevel. that ♦ Electron spin: Electron – Clockwise (+ ½) or Counterclockwise (- ½). – Two electrons per orbital. – Energy comparisons between sublevels / orbitals. – The number of orbitals increases by odd integers. Electron Configuration Electron ♦ The distribution of electrons among the The orbitals of an atom. orbitals ♦ Determined by distributing the atom’s Determined electrons among levels, sublevels, and orbitals based on a set of stated principles. principles. ♦ Ground state: Electrons populate the Ground – Based on the relative energy of the orbitals. lowest energy levels (most stable / can be predicted). predicted). Electron Configurations Configurations ♦Carbon 1s22s22p2 ♦Sample Problems Sample (pg. 135 #8-9) (pg. ♦Homework Problems. Predicting Configuration Predicting ♦ Figure 5-7 pg 133 ♦ Aufbau Principle: Electrons are added Aufbau one at a time to the lowest energy orbital available. available. ♦ Pauli Exclusion Principle: An orbital can Pauli hold a maximum of 2 electrons. hold ♦ Hund’s Rule: Electrons occupy equal Hund’s energy orbitals so that a maximum number of unpaired electrons result. number Orbital Diagrams Orbital ♦ Horizontal diagram depicting how electrons populate orbitals. electrons Carbon : 1s2 2s2 2p2 1s 2s 2p ...
View Full Document

This note was uploaded on 01/28/2011 for the course CHEM 101 taught by Professor Petrovich during the Fall '08 term at N.C. State.

Ask a homework question - tutors are online