1. Spectroscopy Atomic emission spectroscopy (AES)
Atomic absorption spectroscopy (AAS)
UV-visible spectroscopy (UV-Vis)
Infrared (IR) spectroscopy
Nuclear magnetic resonance (NMR) spectroscopy

2. What do spectroscopic techniques tell us?
Type of atom or molecule (qualitative)
Amount of a particular atom or molecule (quantitative)
Structure and bonding of a molecule
What do spectroscopic techniques utilise?
Changes in energy of atoms/molecules in response to electromagnetic radiation

3. The electromagnetic spectrum
Figure 7.1, pg77
The shorter the wavelength, the higher the energy

4. Exciting electrons
Flame test Atomic Emission Spectroscopy (AES) Atomic Absorption Spectroscopy (AAS)
Rely on energy change as electrons move from one energy level to another
Fig 7.7, page79

5. Atomic Emission Spectroscopy
Calcium
Sodium
Mercury
Cadmium
Fig 7.8 and 7.9, page80

6. Atomic Absorption Spectroscopy (AAS)
Fig 7.13, page 83
Can detect over 70 elements
Very sensitive (can detect at concentrations of ppm)
Quantitative (amount of light absorbed proportional to quantity of substance)

7. How do you use this information?
Fig. 7.14, page 83

8. UV-visible spectroscopy
Fig 7.16, p 86
Absorbance spectrum of chlorophyll
Violet (420 nm)
Determining absorbance spectrum of substance
Determining concentration of a substance
Red
(660 nm)
Fig 7.18, p 87
Absorbance is proportional to concentration.
Beer-Lambert Law:
A = cl, where A is absorbance and c is the concentration in in molL-1. The remaining values are constant.
Green
( nm)

9. How does a UV-vis spectrophotometer work?
See Fig 7.15, p86