1. Living By Chemistry SECOND EDITION
Unit 1: ALCHEMY
Matter, Atomic Structure, and Bonding

2. Lesson 17: Technicolor Atoms
Flame Tests

3. ChemCatalyst
These drawings are models that show solid copper, solid copper chloride, and aqueous copper chloride as collections of atoms.
1. Describe each model.
2. What is similar about each model? What is different?
Cu(s)
Solid copper
CuCl2(s)
Solid copper (II) chloride
CuCl2(aq)
Aqueous copper (II) chloride

4. Prepare for lab for your warm up:
Pick up a Chapter 4 Packet.
Obtain your goggles and an apron. RETURN TO YOUR SEAT.
Tie back long hair and roll up long sleeves/remove baggy clothing.
Await further instructions 😃

5. Key Question
What evidence is there that certain atoms are present in a compound?

6. You will be able to:
conduct a flame test and use the results to determine the identity of a compound
interpret evidence of the presence of certain atoms within compounds

7. Prepare for the Lab Work in groups.
You will be using chemicals and fire today. Follow safety instructions.
Wear safety goggles.
Tie back long hair and remove dangling jewelry.
Roll up long sleeves and keep clothing away from flames.
Locate the eye wash, fire blanket, and fire extinguisher before starting the lab.

8. What colors did we see in the flame test
What colors did we see in the flame test? Which compounds produced which colors?
Blue-Green
Red-Purple
Red
Violet
Orange-Yellow
CuCl2
LiNO3
Sr(NO3)2
KCl
NaCl
CuSO4
LiCl
SrCl2
KNO3
Na2CO3

9. What patterns do you notice in the flame test?
The flame color produced is related to the metal atom in each solution. For example, all solutions containing strontium turned the flame red, and all substances containing copper turned the flame blue-green.

10. Predict the flame color for strontium sulfate?
Red, because other strontium compounds produced red flames

11. What evidence do you have that atoms of a certain element produce a flame of a specific color?
Compounds with the same metal atom produce flames of very similar colors

12. Can a flame test be used to identify a metal atom in a compound
Can a flame test be used to identify a metal atom in a compound? Why or why not? What about a nonmetal atom?
It appears that the flame test can be used to determine whether certain metal atoms are present, because each metal atom produces a flame of a certain color. The nonmetal atoms do not seem to affect the color.

13. Discussion Notes
The metal element in each chemical formula appears to be responsible for the flame colors.
Only certain elements produce colorful flames.
Flame test: A test used in the laboratory to look for the presence of certain metal atoms. A sample of a compound is heated in a flame, and the resulting color is noted.

14. What is light?

15. Electromagnetic Spectrum
Electromagnetic Radiation = radiant energy that travels at the speed of light, c (3 x 108 m/s)

16. Why do atoms emit light when heated in a flame?

17. Discussion Notes (cont.)
Sodium Atom, Na

18. Discussion Notes (cont.)
The illustration indicates that the flame colors are associated with movements of the electrons within the sodium atom.
Bohr’s model of the atom came directly from evidence similar to that produced in class yesterday.

19. Electron Configurations.
The purpose of this lecture is to help you understand how electrons are arranged in their energy levels.
You will learn how to write electron configurations, and how these electron arrangements relate to the shape and lay-out of the periodic table.
Because electrons are so important in chemistry, the way in which they are arranged around the nucleus plays a crucial role in determining the chemical reactivity of all the elements.

20. First let’s review a little:
As we have learned, electrons exist in very specific energy levels.
And when these electrons absorb energy…
They get energized up to higher levels.
Actually, the jump to higher levels is not a gradual transition as was just shown.
It is a “quantum” jump, and looks more like this:
Quantum means it happens all at once – instantaneously – because the electron can never exist between levels – not even for a second.

21. Once it is at this higher level (excited state), it doesn’t stay there long.
It quickly drops down to a lower level – again as a quantum leap – and as it does, it gives off a distinct band of light energy.
Also, notice how the electron doesn’t have to drop all the way back down to the lowest level. It can get energized up to any level, and from there it can drop to any lower level. AND the different drops each produce different frequencies of light.
And a 5  2 drop produces violet light
See how an electron dropping from the 3rd level to the 2nd level produced red light
A 4  2 electron drop produces blue light

22. Wrap Up
What evidence is there that certain atoms are present in a compound?
Many metal atoms produce a characteristic colored flame when compounds containing those atoms are heated in a flame.
Flame tests are evidence that elements and compounds are collections of atoms.

23. Check-In
Predict the flame colors produced when heating these substances. Explain your thinking.
• copper (II) carbonate
• calcium chloride