Flame Test Virtual Lab

Flame Test: Virtual Lab Document Problem: How do flame colors vary for different elements? Introduction: The energy levels in atoms and ions are the key to the production and detection of light. Energy levels or "shells" exist for electrons in atoms and molecules. The colors of dyes and other compounds result from electron jumps between these shells or levels, just like the colors of fireworks result from jumps of electrons from one shell to another. Atoms have two kinds of states; a ground state and an excited state. The ground state is the state in which the electrons in an atom are in their lowest energy levels possible (atoms naturally are in the ground state). When elements are heated, some of their electrons get excited and jump to higher energy levels before falling back to their original energy level, releasing energy in small packages of light, or photons. The light emitted has wavelengths and colors that depend on the amount of energy originally absorbed by the electrons. Therefore every element has its own characteristic spectrum. Part 1: Metal Ion Flame Tests Identify the color of the flame for each known metal and then use the data collected to identify two unknown metals. ●​ Define ion. [ an atom or molecule with a net eclectic change due to the loss or gain of one or more electrons ] ●​ What charge does a metal ion form? [ a positive charge ] How does it obtain this charge? [ metal lose ] ●​ How to write the symbol for the metal ions, Barium chloride: Barium is the metal, its symbol is Ba, and charge is +2 (charge is determined by looking at the group number above the column). Final ion symbol = Ba+2 Name of Compound Calcium chloride Copper (II) chloride Metal Ion [ CaC12 ] [ cuCL2 ] Lithium chloride [ LiC1 ] Potassium chloride [ KCL ] Sodium chloride Strontium chloride [ NaC1 ] [ SrC12 ] Unknown #1 [ KCL ] Unknown #2 [ Nac1 ] Observed Flame Color [ Deep orange ] [ blue green ] [ deep red ] [ Pinkish violet ] [ yellowish orange ] [ orange red ] Part 2: Atomic Emission Spectrum Tubes In the flame test you saw a single color as the excited atoms released the energy they gained. But there are billions of excited atoms releasing energy. The excited atoms do not all emit the same energy light because the amount of energy that excited them may differ. The kinds of light energy that can be emitted by excited atoms is unique for an element. The pattern of "lines' or colors emitted is called an emission spectrum that can be used to identify an element. Element Sodium Neon Emission Spectrum List the Color Bands You See [ yellow ] [ green, yellow, red ] Mercury [ blue, green, yellow, red ] Helium [ blue yellow red, green ] Unknown #1 [ green, yellow and red ] Unknown #2 [ yellow ] Analysis Questions: 1.​ Diagram and describe how light is created on an atomic level (Hint: think about the Bohr model and what is happening to the electrons when excited & check out this video link). To create a drawing, click on Insert -> Drawing -> New. [ light is created on a atomic level by Atoms and Energy Level, Excitation, Emission, Photon Wavelength and spectral lines ] 2.​ Looking at Part 1, what are the identities of your unknowns? [ #1 ] What information did you use to draw this conclusion? [ the observed flame colors were similar ] 3.​ Looking at Part 2, answer the following questions: a.​ Which element had the fewest number of clearly visible emission lines? [ sodium and unknown #2 ] b.​ Which element had the greatest number of clearly visible emission lines? [ neon and unknown #1 ] c.​ What are the identities of your unknowns? [ 1 is neon 2 is sodium ] What information did you use to draw this conclusion? [ the emission spectrum matches of the unknowns matches neon and sodium ] 4.​ Using the electromagnetic spectrum diagram below, answer the following questions (remember, energy is proportional to frequency and frequency is inversely proportional to wavelength): a.​ List the metal ion colors observed in this lab from highest to lowest frequency. [ violet > blue > green > yellow > red ] b.​ List the metal ion colors observed in this lab from shortest to longest wavelength. [ violet < blue < green < yellow < red ] c.​ List the metal ion colors observed in this lab from highest to lowest energy. [ violet > blue > green > yellow > red ] 5.​ Colorful light emissions are applicable to everyday life. Think about a time when you might have observed a colorful light emission. Do you think your observation is related to the type of light emission you saw in the lab? Explain. [ In fireworks, metal salts like strontium or barium are heated, causing their electrons to become excited ]