Atoms and the Periodic Table Chapter 8

Visible light consists of electromagnetic waves Electromagnetic radiation: emission and transmission of energy in the form of electromagnetic waves. Speed of light (c) in vacuum = 3.00 x 10 8 m/s Fig. 7.2

Fig. 7.3 The Electromagnetic Spectrum

White light is separated into its color components by a prism

White light is separated into its color components by a diffraction grating The tracks of a compact disc act as a diffraction grating, producing a separation of the colors of white light.

Line Emission Spectrum of Hydrogen Atoms Fig 8.8 (A) Continuous spectrum (B) Line spectrum

Fig 8.9 Three series in the H atom line spectrum

First recorded emission spectrum of the sun (1817) intensity wavelength

1.e − can only have specific (quantized) energy values 2.e − in an orbit does not emit radiant energy 3.Light is emitted as e - moves from a higher orbit to a lower orbit 4.Light must be absorbed to move an e − from a lower to a higher orbit Bohr’s Model of the Atom (1913) Fig 8.10 e-

Fig 8.11 Energy level diagram for the H atom E photon = E H - E L

E = hf Low energyHigh energy E green > E red The bigger the jump, the bluer the photon

Electron configurations of some atoms Valence electrons ≡ electrons in outermost shell

Fig 8.18 Electron dot notation for representative elements 1A 2A3A 8A 4A5A6A7A

Elements are arranged in order of increasing atomic number

Metals good conductors of heat and electricity shiny, ductile, malleable all solids with one exception Nonmetals poor conductors dull appearance, brittle consist of solids, liquids, and gases Physical Properties of the Elements

Period Group Alkali Metal Noble Gas Halogen Alkali Earth Metal p 237

Chemistry In Action Natural abundance of elements in Earth’s crust Natural abundance of elements in human body