EL 3

• The electromagnetic spectrum plays a big role in identifying shells in an atom
• The energy released when an electron moves down energy levels forms a line spectrum or emission spectrum
• When an electron absorbs energy and moves to a higher energy level, it is considered excited
• Atoms can release energy named in the electromagnetic spectrum
• Line spectra help in identifying elements and provide evidence for energy levels in shells
• Each element has a unique emission spectrum, like a barcode, which helps in identifying the element
• Line spectra

  Way of identifying elements and evidence for energy levels in shells
• Components of the electromagnetic spectrum

  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-rays
  • Gamma rays
• The topic of analytical techniques is dedicated to the Psalter syllabus
• When an electron moves back down to a lower energy level, some energy is released
• Electrons can move from one shell to another but cannot be in between
• Line spectrum shows the frequency of light given out when an electron moves down energy levels
• Atomic absorption spectra can also be observed
• Emission spectra

  • Black background with colored bands
• Atomic absorption spectra are used to identify elements by comparing them against a known value or database
• Frequency of radiation absorbed

  Linked to the energy gap between electron shells
• Atomic absorption spectra in hydrogen atoms show potential paths for excited electrons to follow
• Series of lines in atomic absorption spectra are created when electrons move to the same energy level from different ones
• Missing frequencies in atomic absorption spectra result in black bands due to electron absorption
• Electromagnetic radiation is passed through an element in the gas state for atomic absorption spectra
• Number of bands in atomic absorption spectra corresponds to the number of pathways for electron transitions
• Absorption spectra

  • Dark bands on a colored spectrum
• Black bands in atomic absorption spectra indicate frequencies absorbed by electrons
• Electrons absorb specific frequencies corresponding to the energy gap between electron shells in atomic absorption spectra
• Atomic absorption spectra involve two types of line spectrums: emission spectra and absorption spectra
• Electrons falling to the ground state in hydrogen atoms produce lines in the ultraviolet part of the spectrum
• Energy and frequency increase in atomic absorption spectra result in lines getting closer together
• Line spectra in atomic absorption spectra show electrons moving to different energy levels
• Quantum shells in atoms have fixed energy levels and electrons can only exist in these levels, not in between
• Calculating frequency, energy, and wavelength

  Energy gap and frequency are linked by the equation E = H*f, where E is the energy difference between shells, H is Planck's constant, and f is the frequency in Hertz
• Evidence for quantum shells is shown in emission spectra, proving the existence of fixed energy levels in atoms
• Frequency of light being absorbed or emitted by electrons can be calculated using the equation E = H*f, where E is the energy gap between shells, H is Planck's constant, and f is the frequency in Hertz
• Electron movement between energy shells

  Electromagnetic radiation is absorbed to move electrons to higher energy shells and emitted when they drop to lower ones
• Electromagnetic radiation has a fixed frequency as the energy of the shells is fixed
• Definite lines in the emission spectra prove that electrons can only exist in specific quantum levels and not in between
• Energy difference between shells can be calculated using the equation E = H*f, where E is the energy gap between shells, H is Planck's constant, and f is the frequency in Hertz
• Calculating frequency and speed of light

  Speed of light (C) is constant for all electromagnetic radiation and is measured in meters per second. It is linked to frequency and wavelength by the equation C = f*λ, where λ is the wavelength in meters
• Calculating energy difference between shells


  Work out the frequency using the equation C (speed of light) over lambda (wavelength) to get the frequency. Then use Planck's constant and the frequency to calculate the energy gap
• Colors and ions for flame tests

  • Lithium - crimson
  • Sodium - yellowy orange
  • Potassium - lilac
  • Calcium - dark red
  • Barium - green
  • Copper - greeny blue
• Flame tests can be used to identify positive ions in a solid sample by observing the colors emitted and using a spectroscope