Exam 12: Solids: Structures and Applications

Light-emitting diodes are semiconductors that emit light when a current is passed through them. What is the key factor that must be changed to change the wavelength of the emitted light in an LED?

The most common allotrope of carbon is ________

The cubic unit cell of rhenium trioxide (ReO₃) has Re atoms at the corners and O atoms on each of the 12 edges. The atoms touch along the edges. The radii are Re 137 pm and O 73 pm. What is the density of ReO₃?

Gold (Au) has a face-centered cubic structure with a unit cell edge length of 407.8 pm. What is the calculated value of the density of gold in g/cm³ based on this information?

How many nearest neighbor atoms are there around each atom in a face-centered cubic unit cell?

When Si is doped with P, it produces a(n) ________-type semiconductor.

The hybridization of atomic orbitals in diamond is ________

Which unit cell contains the most atoms?

Just as visible light is diffracted by the finely spaced grooves on a CD, electromagnetic radiation in the ________ range has the appropriate wavelength to be diffracted by atoms and electron density in a crystalline lattice.

Which statement regarding the electronic structure of solids is not correct?

If half of the tetrahedral holes in a face-centered cubic unit cell are filled, what must be the stoichiometry of the ionic compound, written as nonhole sites:hole sites in lowest terms?

If a body-centered cubic unit cell has a volume of 1.447 * 10⁸ pm³, what must be the dimension of the cube's edge?

The band structure of semiconductors differs from that of metal conductors in that ________

Why does a pure metal not crystallize in a fluorite or antifluorite unit cell?

In the cubic closest-packed structure of sodium chloride, which ions are touching or nearly touching? I.Sodium ions and sodium ions II.Chloride ions and chloride ions III.Sodium ions and chloride ions

In ionic solids, one ion often occupies a hole in the unit cell defined by the other ion. In a face-centered cubic cell, what are the types and numbers of each hole?

Would you expect the linear allotrope of carbon to conduct electricity? (Fragments of it were first prepared and characterized in 1998.)

In comparing the density of bronze composed of 20% tin to the density of pure copper, ________

Copper crystallizes in a face-centered cubic pattern. How many copper atoms are in each unit cell?

The higher the carbon content in steel, ________