In the solid phase atoms, ions or molecules are arranged in a very organized fashion. In class we will explore three structures frequently encountered in solids. In this PLE we will look at the simplest of these three structures.

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Give me some responses to the questions below and I'll give you some extra credit.

SID#:

Laboratory Section:

1. In the animated rotation below, you should see eight atoms forming a cube. Notice I have used a 'net' design to represent these eight atoms. Another cube whose corners are defined by the center of each of the eight 'net' atoms is also visible. Inside that cube you can see portions of each of the atoms represented in the more solid (red) appearance. If you added all the portions of the atoms within this 'inside' cube, how many atoms do they sum to? (NOTE: the portion of the structure below containing the red solid portions of the atom is called a unit cell. In this case the animation below shows a simple cubic unit cell.)

2. The animation below shows another type of cubic unit cell. What is different about this cubic unit cell compared to the unit cell in Q1? (Hint: How many atoms are within this cubic unit cell compared to the cubic unit cell in Q1?)

3. The animation below shows a third type of cubic unit cell. What is different about this cubic unit cell compared to the unit cell in Q1 and in Q2?

4. Considering the unit cell in Q1, how many atomic radii are needed to equal the edge length of the unit cell cube?

5. If the radius of an atom that crystallizes in a simple cubic unit cell is 1.25 x 10-8 cm what is the volume of the unit cell?

6. If a simple cubic unit cell has the equivalent of one atom, and the atomic mass of the atom is 209 u, what is the mass in grams contained in the unit cell? (Remember 1 u = 1.66 x 10-24 g)

7. Using the data from Q5 and Q6, what is the density of the substance in the unit cell?

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