16.2 Spectroscopy

16.2 Spectroscopy

  • The atoms are drawn together and bonds are created.
    • There is room for another electron in the hydrogen atoms.
  • When two hydrogen atoms are close together, they share each other's electrons, and in this way, the orbit of each atom is completely filled part of the time.
    • The two atoms are pulled together by a rubber band.
  • The atoms are bound into a molecule by the sharing of electrons.
    • The coulomb repulsion of the nuclei keeps the atoms apart.
    • The equilibrium between atoms in a molecule is determined by counter forces.
    • In a similar way, bulk matter is formed.
  • Helium and other elements cannot share electrons with other elements.
  • Both emission and absorption are characteristic of Molecules.
    • Molecules are more complex than atoms because they are more electronic.
    • Each type of molecule has its own spectrum that can be interpreted.
  • Each species has its own absorption and emission spectrum.
    • They can be used to identify atoms and molecules.
    • Basic experiments with atoms and molecules were the first to use microscopes.
  • The products of complex chemical reactions are identified with the help of spectroscopy.
    • In medicine, the concentration of certain atoms and Molecules is determined with the help of Spectroscopy.
    • One can determine the level of mercury in the body by analyzing urine.
    • The blood-sugar level is determined by a chemical reaction in the sample which produces a colored product.
    • The concentration of the colored product is proportional to the blood-sugar level.
  • The basic principles are easy to understand.
    • The sample under investigation is excited by an electric current or flame.
    • The emitted light is identified.
    • The sample is placed in the path of light.
    • The components in the substance are identified by the missing wavelength of the transmitted light.
    • Information about the concentration of the various components in the substance can be provided by the absorption and emission spectrum.
    • In the case of emission, the intensity of the light in the spectrum is proportional to the number of atoms.
    • The concentration can be related to the amount of absorption.
    • The intensity of light is recorded as a function of wavelength.
  • The focusing system creates a beam of light.
    • The beam can be broken up by the prism.
    • The fanned-out spectrum can be photographed and identified.
    • The spectrum is usually detected by a small section at a time.
    • The narrow exit slit intercepts a portion of the spectrum.
    • The whole spectrum is swept past the slit when the prism is rotating.
    • The wavelength impinging on the slit affects the position of the prism.
    • The electrical signal from the light that passes through the slit is proportional to the light intensity.
    • A chart recorder can show the intensity of the signal as a function of wavelength.
  • Spectrometers can be used by relatively unskilled personnel in routine clinical work.
    • The identification and interpretation of the spectrum produced by less well-known molecules requires considerable training and skill.
    • Information about the structure of the molecule can also be found in the spectrum.