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Which element produces a carmine-red flame when heated?
Which element produces a carmine-red flame when heated?
What happens when an electron transitions from a higher energy level to a lower one?
What happens when an electron transitions from a higher energy level to a lower one?
Which of the following represents the energy of a photon emitted or absorbed during an electronic transition?
Which of the following represents the energy of a photon emitted or absorbed during an electronic transition?
In the Bohr model, what does a photon represent?
In the Bohr model, what does a photon represent?
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What is the color of the flame produced by sodium?
What is the color of the flame produced by sodium?
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Which element is associated with producing a green flame?
Which element is associated with producing a green flame?
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According to the Bohr model, electrons are found in:
According to the Bohr model, electrons are found in:
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What effect does the transition from n = 1 to n = 2 have on an electron?
What effect does the transition from n = 1 to n = 2 have on an electron?
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What is the result of the transition from a higher energy level to a lower energy level in atomic emission?
What is the result of the transition from a higher energy level to a lower energy level in atomic emission?
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What does the term 'quantization of energy' imply in atomic spectra?
What does the term 'quantization of energy' imply in atomic spectra?
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How does absorbance relate to concentration in quantitative analysis?
How does absorbance relate to concentration in quantitative analysis?
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What does each element's unique emission line spectrum represent?
What does each element's unique emission line spectrum represent?
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What is indicated by the intensity of an emission line in atomic spectra?
What is indicated by the intensity of an emission line in atomic spectra?
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In flame spectroscopy, what does a higher intensity of the emission spectrum indicate?
In flame spectroscopy, what does a higher intensity of the emission spectrum indicate?
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Which relationship is correct regarding emission intensity and concentration?
Which relationship is correct regarding emission intensity and concentration?
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What is the consequence of nuclear charge and orbital shape on atomic transitions?
What is the consequence of nuclear charge and orbital shape on atomic transitions?
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What type of atoms can be analyzed through atomic absorption spectroscopy?
What type of atoms can be analyzed through atomic absorption spectroscopy?
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Which type of radiation is primarily used in atomic absorption and emission spectroscopy?
Which type of radiation is primarily used in atomic absorption and emission spectroscopy?
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What is the main difference between atomic absorption and atomic emission spectroscopy?
What is the main difference between atomic absorption and atomic emission spectroscopy?
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What type of information does a unique spectrum of an analyte provide in spectroscopy?
What type of information does a unique spectrum of an analyte provide in spectroscopy?
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Which of the following statements about the electronic transition in atomic absorption/emission spectroscopy is correct?
Which of the following statements about the electronic transition in atomic absorption/emission spectroscopy is correct?
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Which of the following is an application of atomic absorption spectroscopy?
Which of the following is an application of atomic absorption spectroscopy?
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Atomic emission spectroscopy primarily measures what type of process?
Atomic emission spectroscopy primarily measures what type of process?
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What does the plot of instrumental response vs. concentration indicate in quantitative analysis?
What does the plot of instrumental response vs. concentration indicate in quantitative analysis?
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What is the ground state electron configuration for sodium (Na)?
What is the ground state electron configuration for sodium (Na)?
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What is the primary characteristic of the ground state of an atom?
What is the primary characteristic of the ground state of an atom?
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In which of the following scenarios will an atom experience an excited state?
In which of the following scenarios will an atom experience an excited state?
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How many electrons can occupy a single atomic orbital?
How many electrons can occupy a single atomic orbital?
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Which of the following orbital configurations corresponds to an excited state of calcium (Ca)?
Which of the following orbital configurations corresponds to an excited state of calcium (Ca)?
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What is the outcome when an electron transitions from a higher energy level to a lower energy level in an atom?
What is the outcome when an electron transitions from a higher energy level to a lower energy level in an atom?
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Which principal components are required for an atomic absorption spectrometer?
Which principal components are required for an atomic absorption spectrometer?
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What is the relationship between wavelength and the energy of absorbed radiation in atomic electron transitions?
What is the relationship between wavelength and the energy of absorbed radiation in atomic electron transitions?
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What is the first step that occurs when an analyte species is aspirated into the flame?
What is the first step that occurs when an analyte species is aspirated into the flame?
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In Atomic Absorption Spectroscopy (AAS), what does 'A' represent in the equation A = abc?
In Atomic Absorption Spectroscopy (AAS), what does 'A' represent in the equation A = abc?
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Which equation best represents the relationship in Atomic Emission Spectroscopy (AES)?
Which equation best represents the relationship in Atomic Emission Spectroscopy (AES)?
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What is required to promote valence electrons to higher energy orbitals in AAS?
What is required to promote valence electrons to higher energy orbitals in AAS?
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In the process of excitation in AES, what type of energy is used?
In the process of excitation in AES, what type of energy is used?
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What is the significance of λmax in the absorption measurement process?
What is the significance of λmax in the absorption measurement process?
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What is the primary mechanism measured in Atomic Absorption Spectroscopy (AAS)?
What is the primary mechanism measured in Atomic Absorption Spectroscopy (AAS)?
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What happens to analyte ions during the second experimental step?
What happens to analyte ions during the second experimental step?
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Which of the following statements correctly describes the detection limits of Atomic Emission Spectroscopy (AES)?
Which of the following statements correctly describes the detection limits of Atomic Emission Spectroscopy (AES)?
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What type of radiation source is used in Atomic Absorption Spectroscopy (AAS)?
What type of radiation source is used in Atomic Absorption Spectroscopy (AAS)?
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Which of the following statements is true about the characteristics of absorbance measurement?
Which of the following statements is true about the characteristics of absorbance measurement?
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What is one of the advantages of Atomic Absorption Spectroscopy (AAS) compared to Atomic Emission Spectroscopy (AES)?
What is one of the advantages of Atomic Absorption Spectroscopy (AAS) compared to Atomic Emission Spectroscopy (AES)?
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In the process of atomization from Mn+(aq) to gaseous Mn, which energy source is primarily utilized in AAS?
In the process of atomization from Mn+(aq) to gaseous Mn, which energy source is primarily utilized in AAS?
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What distinguishes the measurement process in Atomic Emission Spectroscopy (AES) from that in Atomic Absorption Spectroscopy (AAS)?
What distinguishes the measurement process in Atomic Emission Spectroscopy (AES) from that in Atomic Absorption Spectroscopy (AAS)?
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What order of magnitude is typically expected for the linear dynamic range (LDR) in analytical techniques discussed?
What order of magnitude is typically expected for the linear dynamic range (LDR) in analytical techniques discussed?
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Which process is involved in converting an analyte metal species from aqueous ion to gaseous atom?
Which process is involved in converting an analyte metal species from aqueous ion to gaseous atom?
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Study Notes
Atomic Absorption and Emission Theory
- Atomic absorption spectroscopy (AAS) measures the light absorbed by ground-state metal atoms in the gaseous state (M° (g)).
- Atomic emission spectroscopy (AES) measures the light emitted by excited-state metal atoms in the gaseous state (M* (g)).
- Analytes include atoms and ions of metals (e.g., Cu, Fe, Cu²⁺, Fe²⁺).
- Elements detectable by AAS are highlighted in a periodic table.
- AAS and AES can perform qualitative and quantitative analysis (ppm/ppb) of over 70 elements, making AAS a common metal analysis technique.
- Types of radiation used include UV (180-380 nm) and visible light (380-780 nm). Interactions with metals affect valence electron distribution.
- Processes measured include absorption, emission, and fluorescence.
- Electronic transitions involve valence electrons being promoted to higher energy levels, and then falling back to lower energry levels (emission).
- Qualitative analysis information from spectroscopy creates a fingerprint for an element through the element's unique spectrum.
- This unique spectrum is plotted against wavelength for identifying elements.
- Quantitative analysis is achieved by plotting instrumental response against analyte concentration.
- AAS: Absorbance (A) is calculated using the equation A = abc, where 'a' is absorptivity, 'b' is path length and 'c' is concentration. Abs = mC+b.
- AES: Emission Intensity (I) follows the equation I = mC+b.
- Four major experimental steps include converting solvated ions to gaseous atoms, exciting atoms to higher energy levels, measuring absorption/emission , and extracting quantitative data.
- In AAS, a hollow cathode lamp is used to excite atoms. In AES, thermal energy from a flame or plasma sources the atoms.
- The Bohr model of an atom describes electrons orbiting the nucleus in discrete energy levels.
- Electrons can only be in certain discrete orbits with particular energy levels.
- Absorbing or emitting photons causes electrons to change orbitals.
- The emitted or absorbed photon's energy is equal to the difference in energy between the two orbitals.
- The calculated difference in energy levels (E) is related via the formula E = hf = hc/λ.
- Electronic transitions occur when electrons move between orbitals.
- Absorption involves the electron moving to a higher energy level.
- Emission involves the electron returning to a lower energy level.
- An electronic energy level diagram uses horizontal lines to show energy levels, increasing upward.
- Quantum mechanics is used to find probabilities where electrons are likely to be found around the nucleus using orbitals (3-D maps).
- Only 2 electrons of opposite spins can fit in an orbital..
- Electronic configuration for an atom refers to the electrons' arrangement in different orbitals/subshells (s, p, d, f) and specifies the atom's unique arrangement, and ground state configuration is the lowest energy state.
- Ground states as determined from the periodic table for elements such as Na and Ca are given.
- Excited state configurations are presented for Na and Ca, and absorbed or emitted energy corresponds to specific transitions
- The ground-state energy level diagram for Li. Diagrams outlining and illustrating transition of electrons
- The absorption line spectrum generated for Lithium atoms.
Instrumentation for Atomic Absorption/Emission Spectroscopy
- AAS instruments typically consist of a radiation source (hollow cathode lamp), atomization compartment (atom cell), monochromator, and detector.
- AES instruments often have a temperature source (flame or ICP), monochromator, and detector.
- For comparison, AAS uses a radiation source, while AES does not.
- The instrumental layout for a single-beam spectrometer is presented.
- A double-beam atomic absorption spectrometer design is presented.
Comparing AAS and AES
- AAS measures absorption of radiant energy whereas AES measures emission.
- In AAS, energy from an external lamp is absorbed by ground-state atoms, promoting them to higher energy levels.
- In AES, input energy elevates atoms to an excited state thus emitting light at a characteristic wavelength.
- Analytical process details are outlined in a table format.
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Description
Explore the principles of atomic absorption and emission spectroscopy in this quiz. Learn how these techniques measure metal atoms and ions in the gaseous state, and understand their applications in qualitative and quantitative analysis. Test your knowledge on the types of radiation used and the processes involved in spectroscopy.
