Flame Tests and Atomic Spectra Objectives To perform flame tests of metal cations in order to observe their characteristic colors, To perform calculations to determine the frequency and energy of the emitted photons. To relate these results to the types of electronic transitions occurring in these elements. To observe and understand line emission spectra of atoms using gas-discharge tubes. To practice writing electron configurations for these (and other) elements. Electromagnetic radiation is energy in the form of waves. Waves are characterized by their wavelength () and frequency (). Wavelength is defined as the distance between successive crests (or troughs) on a wave, and is measured in meters. Frequency is defined as the number of waves that pass a given point every second, and is measured in 1/seconds (1/s or s-1), or Hertz (Hz). All electromagnetic waves travel at the speed of light (c), or 3.0 108 m/s. The relationship between the wavelength, frequency and speed of a wave is given by the equation: c = (9.1) Electromagnetic radiation also occurs as discreet "packets" called photons. The energy (E) of a photon (in Joules, J) is given by the equation