chap07notes - AP Chemistry A. Allan Chapter 7 Notes -...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
AP Chemistry A. Allan Chapter 7 Notes - Atomic Structure and Periodicity 7.1 Electromagnetic Radiation A. Types of EM Radiation (wavelengths in meters) 10 -12 10 -10 10 -8 4 to 7x10 -7 10 -4 10 -2 1 10 2 10 4 Wavelength increases Frequency decreases Energy decreases Speed is constant = 2.9979 x 10 8 m/sec B. Properties of EM Waves 1. Wavelength ( λ ) a. Distance between two consecutive peaks or troughs in a wave b. Measured in meters (SI system) 2. Frequency ( ν ) a. Number of waves that pass a given point per second b. Measured in hertz (sec -1 ) 3. Speed ( c ) a. Measured in meters/sec 4. Relationship of properties a. c = n l gamma xrays UV visible IR micro Radio waves FM short AM
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
7.2 The Nature of Matter A. Max Planck and Quantum Theory 1. Energy is gained or lost in whole number multiples of the quantity hv Frequency = v Planck's constant = h = 6.626 x 10 -34 J S nhv E = 2. Energy is transferred to matter in packets of energy, each called a quantum B. Einstein and the Particle Nature of Matter 1. EM radiation is a stream of particles - "photons" l hc hv E photon = = 2. Energy and mass are inter-related mc E 2 = C. de Broglie and the Dual Nature of Light 1. Light travels through space as a wave 2. Light transmits energy as a particle 3. Particle's have wavelength, exhibited by diffraction patterns mv h = l a. large particles have very short wavelengths b. All matter exhibits both particle and wave properties 7.3 The Atomic Spectrum of Hydrogen A. Continuous spectra 1. Contains all wavelengths of light B. Bright line spectra 410nm 434nm 486nm 656nm 1. Excited electrons in an atom return to lower energy states 2. Energy is emitted in the form of a photon of definite wavelength 3. Definite change in energy corresponds to: a. Definite frequency b. Definite wavelength l hc hv E = = 4. Only certain energies are possible within any atom
Background image of page 2
7.4 Bohr Model (Neils Bohr, 1913) A. Quantum Model 1. The electron moves around the nucleus only in certain allowed circular orbits 2. Bright line spectra confirms that only certain energies exist in the atom, and atom emits photons with definite wavelengths when the electron returns to a lower energy state 3. Energy levels available to the electron in the hydrogen atom - = - n Z J E x 2 2 18 10 178 . 2 n = an integer Z = nuclear charge J = energy in joules
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
B. Calculating the energy of the emitted photon 1. Calculate electron energy in outer level 2. Calculate electron energy in inner level 3. Calculate the change in energy ( E) E = energy of final state - energy of initial state 4. Use the equation: E hc = l to calculate the wavelength of the emitted photon C. Energy Change in Hydrogen atoms 1. Calculate energy change between any two energy levels - - = - n n J E initial final x 2 2 18 1 1 10 178 . 2 D. Shortcomings of the Bohr Model
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/28/2009 for the course CHEM 102 taught by Professor Freeman during the Spring '08 term at South Carolina.

Page1 / 10

chap07notes - AP Chemistry A. Allan Chapter 7 Notes -...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online