Which method measures light absorbed by atoms dissociated by heat (unionized, unexcited)?

Which method measures light absorbed by atoms dissociated by heat (unionized, unexcited)?

• A. Atomic Absorption Spectrophotometry
• B. Flame Emission Spectroscopy
• C. Atomic Emission Spectroscopy
• D. UV-Vis Spectrophotometry

Answer: (A)

Atomic absorption spectroscopy focuses on how much light is absorbed by neutral, ground-state atoms that have been produced by heating the sample (flame atomization). When the sample is heated, it dissociates into free, unionized atoms. These ground-state atoms absorb photons at very specific wavelengths unique to each element. The instrument measures the decrease in light intensity as it passes through the flame, and that absorbance is proportional to the element’s concentration (Beer-Lambert law). This differs from flame emission spectroscopy, which detects light emitted by excited atoms, or UV-Vis spectrophotometry, which usually measures absorption by molecules in solution, and from atomic emission spectroscopy, which relies on light emitted from excited atoms in a high-energy source. So the method described is Atomic Absorption Spectrophotometry.

Atomic absorption spectroscopy focuses on how much light is absorbed by neutral, ground-state atoms that have been produced by heating the sample (flame atomization). When the sample is heated, it dissociates into free, unionized atoms. These ground-state atoms absorb photons at very specific wavelengths unique to each element. The instrument measures the decrease in light intensity as it passes through the flame, and that absorbance is proportional to the element’s concentration (Beer-Lambert law).

This differs from flame emission spectroscopy, which detects light emitted by excited atoms, or UV-Vis spectrophotometry, which usually measures absorption by molecules in solution, and from atomic emission spectroscopy, which relies on light emitted from excited atoms in a high-energy source. So the method described is Atomic Absorption Spectrophotometry.