Spectroscopy Lab
Introduction:
The objective of this lab was to understand the Bohr model, learn to use a spectroscope and spectrometer, understand how models of the atom have been made and changed based on emission lines and spectroscopy, and to learn how emission lines and spectroscopy have helped to discover the existence of new materials.
The Bohr model was created by a man named Niels Bohr in 1913, to explain the movement of electrons inside an atom and their purpose. This model shows that electrons are in a constant orbit around the nucleus of the atom, following certain paths laid out by the atom specific to the material it makes up. Any given atom has a number of orbitals specific to it's substance which is followed by the electrons making up that atom. When a particle of energy (this could be light, or a quickly moving particle) hits an electron, more energy is added to the electron causing it to become excited and 'jump' out of its orbital to another orbital farther from the nucleus. The electron then falls back inward to the nucleus where it requires less energy to orbit the nucleus. When the electron 'falls' back inward to the nucleus, it releases the energy gained from being hit with light or heat. This energy being given off is what makes the color of light or flame that is seen when a substance is heated to very high temperatures. The farther the drop of the electron, the more energy the light being given off will have. The distance between the subshells, as well as the number of subshells surrounding the atom will determine the color and energy of the light energy being let off from this action.
The Bohr and quantum mechanical models are examples of the atomic theory; the idea that all matter is composed of tiny particles in constant motion. This idea was first shared by Greek philosophers Leucippus and Democritus in the 5th century B.C. However was not accepted until the 18th century through studying the nature of gases. Both models are representations of how electrons work in an atom. They are very similar, and both show where electrons are located in an atom, however the Bohr model shows the exact spot where an electron should be, the number of orbits around the nucleus and the exact number and location, of electrons on each ring. The quantum mechanical model is the most current and accurate model of the electron, and shows the general location of electrons in an atom through a probability cloud illustrating where an electron is most likely to be at any given point.
Atomic emission lines are lines of color created when electrons in an atom fall from an excited state around the nucleus of an atom, letting off extra energy in the form of color. Based on these colors (emission lines), an element can be identified, as each substance is made up of atoms which each have a certain number of orbits and electrons. Because the color of light let off by the release of energy varies based on the distance the electron 'falls' back towards the nucleus, a new pattern of emission lines is created for each element in the periodic table. For example, when burning an element, the flame may turn a bright red color (depending on the element being burned) because the light energy being given off from the electrons after they have been heated, could be giving off certain colors which all blend together and look like the flame seen when the element is burned. However, the flame color is many colors being let off at the same time by excited electrons, so the individual colors would not be seen except as emission lines.
Spectroscopy is the study of using light to identify matter, this has been used many times throughout history to discover new elements and to identify those already discovered. A spectrometer is an instrument used to see element's emission lines and to identify elements based on their lines of color. A spectrometer works by taking in light and breaking it into it's spectral components known as emission lines, so the element's light can be seen as a pattern of emission lines specific to the element. When an element's electrons are charged through applying energy, a spectrometer can be used to examine the emission lines created by the electrons letting off color. A spectrometer has been a key instrument to discovering new elements and identifying the ones already known of. In one case, a scientist used a spectrometer to look at the sun during a solar eclipse and discovered the element helium. The emission lines of helium were different than any seen before, therefore helium was deemed a new element based on the emission lines seen through a spectrometer.
Part 1:
Results:
Table 1: Substance and Flame Color
Solution
Flame Color
NaCl
Deep Orange
CuCl2
Light blue w/ flecks of green
LiCl
Deep Orange
KCI
Peach orange
CaCl2
Red orange
SrCl2
Bright red
CaCO3
Violet blue
Na2Co3
Orange
K2SO4
Violet/blue
CaSO4
Semi-dark blue
Unknown 1
Deep orange
Unknown 2
Deep orange w/pink red
Discussion:
Part I of this lab tested elements based on their flame color, using the results gathered, elements unknown 1 and unknown 2 were identified. This part of the lab showed that there is no relationship between the color of the solutions being burned, and the color of the resulting flame. Each of the liquids were clear in color with the exception of the copper (CuCl2) which was blue. Table 1 (above) shows that even when every solution had the same color, many still burned a different colored flame than the other solutions of the same clear color. For example, CaCo3 is a clear solution and when burned, created a violet blue colored flame. SrCl2 was also a clear liquid, however rather than the flame color being violet blue also, (as would be expected if the color of the solution did affect the color of the flame) the flame created from the reaction was bright red. If the color of the solution burned did affect the color of the flame, it would be expected that every flame would be the same color, with the exception of the copper which would burn a different color than the rest of the clear liquids.
Based on Table 1 (above) it can be concluded that neither the anions (non-metals) or the cations (metals) affect the color of the flame created when solutions are burned, but rather the combination of both the anions and cations. Table 1 (above) shows: when finding if the non-metals (elements on the right side of the solution) are the elements which determine the color of the flame, it is suggested that the anions are not the cause for the difference in color of the flame. Of the solutions tested, six out of twelve of the solutions contained chlorine (Cl). Table 1 shows that the color of flame varied even within the solutions which contained chlorine. This variation in flame color (even though each of the six solutions contained chlorine) suggests that the non-metal component of the solution is not the cause of the flame color variation. The information in Table 1 also suggests that it is not the metal component of the solution which creates a variation in flame color. Table 1 shows the solutions with similar components, how although the metal part of the solution is the same, the flame color is different. For example, potassium (K) is found in two different solutions, however each solution burned a different colored flame. When KCl was burned, it produced a peach orange colored flame, and when K2SO4 was burned, a violet blue flame was produced. This evidence suggests that the metal component of the solution burned does not affect the color of the flame. Based on the evidence discovered in Table 1, it is suggested that neither the anions or the cations determine the color of the flame, but rather a combination of all the components in the solution. If either the metals or non-metals showed a constant flame color based on which metal or non-metal was present, this may show that the flame color is dependent on one of these components. However, the fact that even when these metal or non-metal components did match up, and the flame color still varied, suggests that the color of the flame depends on a combination of both the anions and cations, rather than one or the other.
Along with the known solutions tested, two unknown solutions were also present and tested along with the others in the same manner. Unknown 1 let off a flame of a deep orange color, by comparing these results with others in Table 1 (above) it was suggested that the unknown 1 could be identified as sodium chloride (NaCl). The solutions which flame was orange in color were compared to each other, to discover which elements were most commonly present when an orange flame appeared. Through this process, it was found that the anion chlorine (Cl) was present the most times in the solution, suggesting that unknown 1 consists partly of Cl. The cations then underwent the same process and sodium (Na) was found in the most solutions which let off an orange color when burned. This suggests that the unknown 1 solution consisted partly of sodium (Na), suggesting that the unknown 1 solution is sodium chloride (NaCl). Unknown 2 underwent the same process as unknown solution 1, and based on the evidence collected through this process, it was suggested that the solution unknown 2 can be identified as calcium chloride (CaCl). Each of the elements present in this solution were most often present in the solutions tested which burned a deep orange/pink red, just as the unknown 2 solution flame color burned. To raise the level of certainty in this part of the lab, a list of specific colors could have been used to ensure that each flame color identification is exact, and the difference between similar looking flames is seen and accounted for. This would ensure that the elements burned would be correctly identified.
The objective of this lab was to understand the Bohr model, learn to use a spectroscope and spectrometer, understand how models of the atom have been made and changed based on emission lines and spectroscopy, and to learn how emission lines and spectroscopy have helped to discover the existence of new materials.
The Bohr model was created by a man named Niels Bohr in 1913, to explain the movement of electrons inside an atom and their purpose. This model shows that electrons are in a constant orbit around the nucleus of the atom, following certain paths laid out by the atom specific to the material it makes up. Any given atom has a number of orbitals specific to it's substance which is followed by the electrons making up that atom. When a particle of energy (this could be light, or a quickly moving particle) hits an electron, more energy is added to the electron causing it to become excited and 'jump' out of its orbital to another orbital farther from the nucleus. The electron then falls back inward to the nucleus where it requires less energy to orbit the nucleus. When the electron 'falls' back inward to the nucleus, it releases the energy gained from being hit with light or heat. This energy being given off is what makes the color of light or flame that is seen when a substance is heated to very high temperatures. The farther the drop of the electron, the more energy the light being given off will have. The distance between the subshells, as well as the number of subshells surrounding the atom will determine the color and energy of the light energy being let off from this action.
The Bohr and quantum mechanical models are examples of the atomic theory; the idea that all matter is composed of tiny particles in constant motion. This idea was first shared by Greek philosophers Leucippus and Democritus in the 5th century B.C. However was not accepted until the 18th century through studying the nature of gases. Both models are representations of how electrons work in an atom. They are very similar, and both show where electrons are located in an atom, however the Bohr model shows the exact spot where an electron should be, the number of orbits around the nucleus and the exact number and location, of electrons on each ring. The quantum mechanical model is the most current and accurate model of the electron, and shows the general location of electrons in an atom through a probability cloud illustrating where an electron is most likely to be at any given point.
Atomic emission lines are lines of color created when electrons in an atom fall from an excited state around the nucleus of an atom, letting off extra energy in the form of color. Based on these colors (emission lines), an element can be identified, as each substance is made up of atoms which each have a certain number of orbits and electrons. Because the color of light let off by the release of energy varies based on the distance the electron 'falls' back towards the nucleus, a new pattern of emission lines is created for each element in the periodic table. For example, when burning an element, the flame may turn a bright red color (depending on the element being burned) because the light energy being given off from the electrons after they have been heated, could be giving off certain colors which all blend together and look like the flame seen when the element is burned. However, the flame color is many colors being let off at the same time by excited electrons, so the individual colors would not be seen except as emission lines.
Spectroscopy is the study of using light to identify matter, this has been used many times throughout history to discover new elements and to identify those already discovered. A spectrometer is an instrument used to see element's emission lines and to identify elements based on their lines of color. A spectrometer works by taking in light and breaking it into it's spectral components known as emission lines, so the element's light can be seen as a pattern of emission lines specific to the element. When an element's electrons are charged through applying energy, a spectrometer can be used to examine the emission lines created by the electrons letting off color. A spectrometer has been a key instrument to discovering new elements and identifying the ones already known of. In one case, a scientist used a spectrometer to look at the sun during a solar eclipse and discovered the element helium. The emission lines of helium were different than any seen before, therefore helium was deemed a new element based on the emission lines seen through a spectrometer.
Part 1:
Results:
Table 1: Substance and Flame Color
Solution
Flame Color
NaCl
Deep Orange
CuCl2
Light blue w/ flecks of green
LiCl
Deep Orange
KCI
Peach orange
CaCl2
Red orange
SrCl2
Bright red
CaCO3
Violet blue
Na2Co3
Orange
K2SO4
Violet/blue
CaSO4
Semi-dark blue
Unknown 1
Deep orange
Unknown 2
Deep orange w/pink red
Discussion:
Part I of this lab tested elements based on their flame color, using the results gathered, elements unknown 1 and unknown 2 were identified. This part of the lab showed that there is no relationship between the color of the solutions being burned, and the color of the resulting flame. Each of the liquids were clear in color with the exception of the copper (CuCl2) which was blue. Table 1 (above) shows that even when every solution had the same color, many still burned a different colored flame than the other solutions of the same clear color. For example, CaCo3 is a clear solution and when burned, created a violet blue colored flame. SrCl2 was also a clear liquid, however rather than the flame color being violet blue also, (as would be expected if the color of the solution did affect the color of the flame) the flame created from the reaction was bright red. If the color of the solution burned did affect the color of the flame, it would be expected that every flame would be the same color, with the exception of the copper which would burn a different color than the rest of the clear liquids.
Based on Table 1 (above) it can be concluded that neither the anions (non-metals) or the cations (metals) affect the color of the flame created when solutions are burned, but rather the combination of both the anions and cations. Table 1 (above) shows: when finding if the non-metals (elements on the right side of the solution) are the elements which determine the color of the flame, it is suggested that the anions are not the cause for the difference in color of the flame. Of the solutions tested, six out of twelve of the solutions contained chlorine (Cl). Table 1 shows that the color of flame varied even within the solutions which contained chlorine. This variation in flame color (even though each of the six solutions contained chlorine) suggests that the non-metal component of the solution is not the cause of the flame color variation. The information in Table 1 also suggests that it is not the metal component of the solution which creates a variation in flame color. Table 1 shows the solutions with similar components, how although the metal part of the solution is the same, the flame color is different. For example, potassium (K) is found in two different solutions, however each solution burned a different colored flame. When KCl was burned, it produced a peach orange colored flame, and when K2SO4 was burned, a violet blue flame was produced. This evidence suggests that the metal component of the solution burned does not affect the color of the flame. Based on the evidence discovered in Table 1, it is suggested that neither the anions or the cations determine the color of the flame, but rather a combination of all the components in the solution. If either the metals or non-metals showed a constant flame color based on which metal or non-metal was present, this may show that the flame color is dependent on one of these components. However, the fact that even when these metal or non-metal components did match up, and the flame color still varied, suggests that the color of the flame depends on a combination of both the anions and cations, rather than one or the other.
Along with the known solutions tested, two unknown solutions were also present and tested along with the others in the same manner. Unknown 1 let off a flame of a deep orange color, by comparing these results with others in Table 1 (above) it was suggested that the unknown 1 could be identified as sodium chloride (NaCl). The solutions which flame was orange in color were compared to each other, to discover which elements were most commonly present when an orange flame appeared. Through this process, it was found that the anion chlorine (Cl) was present the most times in the solution, suggesting that unknown 1 consists partly of Cl. The cations then underwent the same process and sodium (Na) was found in the most solutions which let off an orange color when burned. This suggests that the unknown 1 solution consisted partly of sodium (Na), suggesting that the unknown 1 solution is sodium chloride (NaCl). Unknown 2 underwent the same process as unknown solution 1, and based on the evidence collected through this process, it was suggested that the solution unknown 2 can be identified as calcium chloride (CaCl). Each of the elements present in this solution were most often present in the solutions tested which burned a deep orange/pink red, just as the unknown 2 solution flame color burned. To raise the level of certainty in this part of the lab, a list of specific colors could have been used to ensure that each flame color identification is exact, and the difference between similar looking flames is seen and accounted for. This would ensure that the elements burned would be correctly identified.