Name: ___________________________
Nomenclature, Formula Writing, Various Electron Configurations, and Orbital Diagrams Lab
a.k.a. the Flame Test and Spectroscope Lab
Purpose: *To provide an opportunity to develop our skills in nomenclature, formula writing, writing various
electron configurations, and drawing orbital diagrams.
*To perform flame tests in order to recognize that metal cations, when strongly heated by a lab burner’s
flame, will release energy in the form of light. The heat of the flame excites the electrons of the metals ions,
causing them to emit visible light. The flame test may be used to visually determine the identity of an unknown
metal or metalloid ion, as flame test colors are well established and reproducible.
Flame colors are produced from the movement of the electrons in the metal ions present in compounds.
For example, a sodium ion in the unexcited, or ground, state has the electron configuration: 1s 22s22p6.
When you heat sodium ions, the electrons receive the energy from the flame and use the energy to “jump”
into any of the empty orbitals at higher energy levels - for example, into the 7s or 6p or 4d or whatever,
depending on how much energy a particular electron happens to absorb from the flame.
Because the electrons are now at a higher and more energetically unstable level, they tend to fall back down
to where they were before - but not necessarily all in one jump. An electron which had been excited from
the 2p sublevel to an orbital in the 7th energy level, for example, might jump back to the 2p level in one
leap, in which case a certain amount of energy would be emitted back out of the atom…..and potentially
show up as visible light of a particular color. [I say “potentially” because, the energy emitted could also
show up as in-visible light (uv rays, infrared rays.] Additionally, the electron might leap back to its original
sublevel in two (or more) smaller hops: stopping briefly at the 5th energy level and then continuing back to
the 2p sublevel. In that case, you could potentially see 2 different colors of visible light (because each time
the electron stops at an energy level, it releases a photon (or packet) of light).
All of this happens very quickly, and as a result of all these jumps, a spectrum of specific colors is routinely
produced. The color you would see with your unaided eyes would be a combination of all the individual
colors – what you will see today during the flame tests is a blending such as this. The exact sizes of the
possible jumps between energy levels varies from one metal ion to another. That means that each different
metal ion will produce one set of distinct jumps, and so a distinct flame color.
*To understand the role that an atom’s electrons play in producing an element’s characteristic flame test color by
further analyzing some light emitted using an apparatus consisting of a “gas discharge tube” and a “spectroscope”.
When separated through a prism, the visible colors of light seen from an element would be called the element’s
“emission spectrum”. The name of the emission spectrum, from our simplest element, hydrogen, is called the “Balmer
series”. Hopefully, this study today will enable you to understand how the Balmer series contributed substantially to
our understanding of atomic structure, specifically, an atom’s energy levels.
In order to understand emission spectra, first consider what light which has been passed through a prism
looks like. The spectroscope you use today will function similarly to a prism. Thus, if a given element were
to emit “all the colors of the rainbow”, you would see, well, all the colors of the rainbow; but, each element
doesn’t do that! In fact, an element with just a few electrons might only emit a few distinct colors from the
rainbow. Expect to see short bright vertical colored lines, within a wide black background.
An element’s emission spectrum is unique to that element: Every element has a signature emission spectrum that can
be used to differentiate between one element and another, similar to how a fingerprint can identify one person from
another. Emission spectra are well-established, and are used by astrophysicists to study the presence of
elements burning in stars from distant galaxies.
Procedure:
Spectroscope Stations: Only “qualitative data” need be recorded today. That means, no measurements!
You will look at emission spectra from hydrogen, helium, nitrogen, neon, mercury, and emissions from an ordinary
tungsten filament light bulb. Go to an empty spectroscope. Take a look. Answer questions below. Prior to leaving
class today, your teacher will show you an interactive website, if she can get shockwave player installed tonight, which
will help you understand how an atom generates light emissions.
Flame Stations: The metal cations that you will observe today are manganese, copper, lithium, potassium,
sodium, calcium, barium, and strontium. Cation’s don’t exist alone – you’ll always find them hooked up with
anions. Chloride is the anion present today. Chloride doesn’t interfere with the flame color. After noting the pretty
colors (below), you’ll be asked to begin working on the nomenclature, formula writing, electron configurations and
orbital diagrams.
Results:
1. Briefly describe what you see when you look at a glowing tungsten filament (light bulb) through a spectroscope.
2. Briefly compare and contrast the emission spectra of hydrogen, helium, and mercury.
3. Briefly compare and contrast the emission spectra of nitrogen and neon.
4. Fill in the color of the flame test for each of the following metal cations:
a. Manganese (Mn):
e. Sodium (Na):
b. Copper (Cu):
f. Calcium (Ca):
c. Lithium (Li):
g. Barium (Ba):
d. Potassium (K):
h. Strontium (Sr):
5. Draw the orbital diagram for an atom of the element, manganese.
6. Draw the orbital diagram for the manganese(II) ion.
7. What are the two different names for two common ions of copper? (do NOT say “positive”… be more specific)
8. What are the two different symbols for the two common ions of copper? (do NOT write “Cu”… be more specific)
9. What is the electron configuration for an atom of lithium?
10. What is the electron configuration for the lithium ion?
11. Draw an orbital diagram for an atom of potassium.
12. Draw an orbital diagram for a potassium ion.
13. What is the charge of an atom of sodium?
14. What is the charge of a sodium ion? (do NOT say “positive”…. Be more specific).
15. What is the abbreviated electron configuration for strontium?
16. What is the electron configuration for an atom of calcium?
17. What is the electron configuration for a calcium ion?
18. What is the abbreviated electron configuration for an atom of barium?
19. You used a solution containing ions of manganese(II) and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
20. You used a solution containing ions of copper(I) and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
21.
You used a solution containing ions of copper(II) and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
22. You used a solution containing ions of lithium and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
23. You used a solution containing ions of potassium and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
24. You used a solution containing ions of sodium and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
25. You used a solution containing ions of calcium and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
26. You used a solution containing ions of barium and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.
27. You used a solution containing ions of strontium and ions of chlorine.
a. Write the formula for the compound in the solution.
b. Name the compound in the solution.