Use the NIST Atomic Spectral Database to assign the four brightest spectral lines for Li and He. In a table, list the transition wavelength, lower and upper state electron configurations, the lower and upper state term symbols, the lower and upper state J 71 values, and the lower and upper state degeneracies (http://physics.nist.gov/PhysRefData/ASD/lines_form.html). Hint, use a minimum Aki value to reduce the number of lines reported by the NIST search.

Abstract This physical chemistry laboratory exercise will have students work with provided emission spectra for several elements and data collected on the NIST Atomic Spectral Database. First, students will develop a method for calculating what wavelengths of visible light are associated with the most intense spectral lines in the provided visible emission spectra. Then, the NIST Atomic Spectral Database will be accessed in order to identify select properties associated with the four most intense spectral lines. Introduction The emission process can be described in two general parts. Initially, energy is absorbed by an atom, and its electrons can be moved into higher energy (excited) states from their ground state The excitedrelectrons then "relax" and drop back to their ground state. Energy lost during an electron's retaxation process is emitted as a photon. Recall that the energy of a photon is photon upper E lower Where Ephoton is the energy of the photon that is emitted when the emitter drops from an upper energy state to a lower energy state, h is Planck's constant, c is the speed of light, and v is the wavenumber. Remember that the length units should match for c and v This is a good time to revisit a few concepts. Atoms and molecules possess discrete energy levels their energy levels are quantized and not continuous. Using eq 7.1, it is possible to determine the energy associated with a specific excited state to ground state transition if we can determine the wavelength of emitted light. Also keep in mind that there are selection rules that limit the type of transitions we can expect to observe. All of these points are reflected in an elemental or ionic emission spectrum. The visible light spectrum falls within a fairly narrow range of wavelengths, from approximately 400 to 700 nm. Even so, discrete spectral lines are seen in each element's visible light emission spectrum. Each (take some time to reflect on why that would be), each element also has a unique emission spectrum. This provides a diagnostic tool for determining the composition of a sample. As an example, the elements present in celestial objects can be determined by the light that they produce line represents one possible transition. Since each element has unique energy levels Some of the transitions observed in this lab exercise involve d-orbitals. As such, a discussion regarding d-orbitals and related selection rules is necessary at this point. The first goal is to determine which character table should be used. Start by observing the shape and relative orientations of the d-orbitals. Refer to Figure 1 below

Use a ruler to calibrate the spectral limits in the figure above. In other words, what are the right and left limits in nm, and what is the equation that converts distance on this page in cm to spectral units of nm? This âcalibrationâ will help you with the next item.

Use the NIST Atomic Spectral Database to assign the three bright spectral lines in the hydrogen spectrum.

Abstract This physical chemistry laboratory exercise will have students work with provided emission spectra for several elements and data collected on the NIST Atomic Spectral Database. First, students will develop a method for calculating what wavelengths of visible light are associated with the most intense spectral lines in the provided visible emission spectra. Then, the NIST Atomic Spectral Database will be accessed in order to identify select properties associated with the four most intense spectral lines. Introduction The emission process can be described in two general parts. Initially, energy is absorbed by an atom, and its electrons can be moved into higher energy (excited) states from their ground state The excitedrelectrons then "relax" and drop back to their ground state. Energy lost during an electron's retaxation process is emitted as a photon. Recall that the energy of a photon is photon upper E lower Where Ephoton is the energy of the photon that is emitted when the emitter drops from an upper energy state to a lower energy state, h is Planck's constant, c is the speed of light, and v is the wavenumber. Remember that the length units should match for c and v This is a good time to revisit a few concepts. Atoms and molecules possess discrete energy levels their energy levels are quantized and not continuous. Using eq 7.1, it is possible to determine the energy associated with a specific excited state to ground state transition if we can determine the wavelength of emitted light. Also keep in mind that there are selection rules that limit the type of transitions we can expect to observe. All of these points are reflected in an elemental or ionic emission spectrum. The visible light spectrum falls within a fairly narrow range of wavelengths, from approximately 400 to 700 nm. Even so, discrete spectral lines are seen in each element's visible light emission spectrum. Each (take some time to reflect on why that would be), each element also has a unique emission spectrum. This provides a diagnostic tool for determining the composition of a sample. As an example, the elements present in celestial objects can be determined by the light that they produce line represents one possible transition. Since each element has unique energy levels Some of the transitions observed in this lab exercise involve d-orbitals. As such, a discussion regarding d-orbitals and related selection rules is necessary at this point. The first goal is to determine which character table should be used. Start by observing the shape and relative orientations of the d-orbitals. Refer to Figure 1 below

1. Which of the following is NOT an example of evolution?

(a) Beak size in a population of birds becomes larger from onegeneration to the next

because larger beaked birds had higher reproductive success andpassed the trait to

their offspring

(b) Over long periods of time whales gradually lost theirhindlimbs

(c) When traveling to high altitude, human physiology changes toaccommodate lower

oxygen levels

(d) All of the above are examples of evolution

2. Jean-Baptiste Lamarck proposed:

(a) bacteria represent some of the youngest species on earth

(b) organisms can adapt to their environment

(c) life arises spontaneously

(d) all of the above

(e) none of the above

3. Carlos Linnaeus:

(a) devised a system of taxonomy that is still used today

(b) accepted the idea that most of lifeï¿½s diversity arosethrough the process of evolution

(c) believed that lifeï¿½s diversity reflected a divine plan

(d) a and b are correct

(e) a and c are correct

4. On what point(s) would Charles Darwin and Jean-BaptisteLamarck have agreed:

(a) adaptation occurs when individuals change to adapt to theirenvironment

(b) life is spontaneously generated all the time

(c) species give rise to new species

(d) simple organisms have existed for a shorter period of timethan complex organisms

(e) they would have disagreed on all of these points

5. Several scientists have argued that life likely existed asfar back as 3.7 billion years ago. They base this claim on:

(a) the presence of biomarkers in rocks of that age

(b) fossils of stromatolites in rocks of that age

(c) fossils of photosynthetic bacteria in rocks of that age

(d) the presence of tiny blobs of mineral-rich fluids in rocksof that age

6. The earliest generally accepted fossils of living organismsare:

(a) yeasts

(b) stromatolites

(c) zircons

(d) carbon isotopes

7. The transition of from single-celled to multi-celledorganisms:

(a) happened once

(b) happened on multiple occasions

(c) occurred before the origin of eukaryotes

(d) a and c are correct

(e) b and c are correct

8. The earliest animal fossils appear similar to modern day:

(a) sponges

(b) archaea

(c) fungi

(d) jellyfish

9. Tetrapods include:

(a) organisms descended from ancestors with four limbs

(b) birds

(c) whales

(d) all of the above

10. Based on current fossil evidence:

(a) whales were likely fully aquatic before they evolvedpeg-like teeth or baleen

(b) evolution of baleen forced whales to become fullyaquatic

(c) the teeth of extinct whales such as Dorudon were similar tothose of extinct land

mammals

(d) a and c are correct

(e) b and c are correct

NMC101H1 Lecture 9: Lecture 9

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