Last modified: Wed 12/31/1969 06:00:00 pm

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.

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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 Solids button on the left side of the screen to reveal a list of structures. Click on the PC (Primitive cubic) structure to see a simple cubic structure and to rotate the structure. Once the page are satisfactory continue with Q1.

1. In the PC structure select small radii to see a similar image as shown below (although the color is different).

(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 bounding box and the eight atoms. You can switch between the small radius and large radius views. Measure the distance from the center of one of the atoms to the center of the adjacent atom on the same edge. 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. See the figure below. )

Enter the distance between the two centers.


2. Convert the distance from nanometers to meters. (1 nm = 1 x 10-9 meters)


3a. Knowing the distance between the two atoms corresponds to one edge of the cube. Calculate the volume of the cube. (NOTE: Calculate the volume in cubic meters, not cubic nanometers.)


b) Is this a big number or a small number?

4. Since two atoms are just touching each other on this cube edge, and knowing the edge length of the cube, what is the radius of one of the atoms?


5. Calculate the volume of the atom using the relationship for the volume of a sphere (V = 4/3*pi*r3)


6. Assuming that each corner atom (their are eight corner atoms) contributes one-eighth of its volume to the cube how many total atoms end up being inside the cube volume?


7. OK, this may be a tough question...using your answers in Q6a, Q8 and Q9 calculate the percent of empty space in the simple cube structure.


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

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