Last modified: Wed 03/09/2016 10:38:16 am
BCE

Do not press the RETURN or ENTER key while you are answering these questions. Your browser will interpret either the same as clicking on the Submnit key.

Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.

First Name:

Last Name:

School:

Click on the Models360 link to open the page in a new tab. In the right side of the screen click on the Solids tab. In the new screen click on the Primary Metallic Structures button on the left side of the screen to reveal a list of structures. Click on the CCP (FCC) Metals (Face Center Cubic)) structure to see a face centered cubic structure and to rotate the structure.

(NOTE: You can move the image by placing the mouse in the Jmol viewing window then clicking and hold the button down and moving the mouse.) Move the image around a little so you can see the cubic nature of the atoms. You might try to align the image so you can see what portion of a face-centered atom is inside the unit cell. To measure the distance between the two atom be sure the mouse is in the center of the first atom and double click the mouse (you may see the cursor change from an arrow to a cross), then move the mouse to the center of the adjacent atom and double click again. A distance in nanometer should appear along a dotted line between the two atoms. Here are a few extra images;

 

1. Measure the distance between two corner atoms sharing an edge of the cube.

nm

2. Measure the distance between two corner atoms that share the face diagonal in the cube.

nm

3. How many atom radii lie along the face diagonal. (You may wish to increase the atom size to help you visualize how many atoms are on a body diagonal.

atoms

4. Use Q2 and Q3 to determine the radius of the atom in the FCC cube.

nm

5. Convert the radius distance from nanometers to meters. (1 nm = 1 x 10-9 meters) (NOTE: If you use scientific notation, enter 1.44 x 10-10 as 1.44e-10)

meters

6. Knowing the edge length of the cube. Calculate the volume of the cube

m3

7. Use the atom radius from Q4 to calculate the volume of the atom using the relationship for the volume of a sphere (V = 4/3*pi*r3)

m3

8. Assuming that each corner atom (their are eight corner atoms) contributes one-eighth of its volume to the cube, and any face-centered atoms contribute half of themselves to the cube, how many total atoms end up being inside the FCC cube volume? (Hint: Look at Figure 11.34 in your textbook.)

atoms

9. OK, this may be a tough question...using your answers in Q6, Q7 and Q8 calculate the percent of empty space in the face-centered cubic structure. (NOTE: Recall the empty space in a simple cube was 47.6%.)

%

10. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

11. If there is one question you would like to have answered in lecture, what would that question be?