Learning Objectives For Test 3

Chapter 3, Structures of Simple Solids

Homework.  Exercises:  2-6, 9, 12, 14-18.  Problems:  6, 7, 9, 11, 13, 14

Description of the structures of solids

3.1  Unit cells and the description of crystal structures

Given a lattice, sketch a unit cell.

Recognize different types of centering.

Make a three-dimensional sketch of the rock salt structure.

Determine the number of atoms belonging to a given unit cell.

Given a three dimensional model of a unit cell, sketch a projection diagram, and vice versa.   Exercises:  2

3.2  The close packing of spheres

Describe the difference between the two closest packed lattices, hcp and fcc.  Exercises:  3

3.3  Holes in close-packed structures

Given a model of a common crystal structure type, describe it in terms of a lattice, and holes, and coordination numbers.  Exercises:  4, 5

Identify the locations of holes in a close-packed structure. 

Know the relative number of holes.

Structures of metals and alloys

3.4  Polytypism

Recognize polytypes.

3.5  Nonclose-packed structures

Describe two non-close-packed structures.

3.6  Polymorphism of metals

Recognize polymorphism.

3.7  Atomic radii of metals

Describe (qualitatively) what happens to metallic (and ionic) radii when the coordination number increases (or decreases).  Exercises:  6

3.8  Alloys

Describe the two main types of alloys.

Predict whether a substitutional or interstitial alloy will result when two given elements are combined.

Ionic solids

3.9  Characteristic structures of ionic solids

Given a structure, describe it in terms of a lattice type and holes.

3.10       Rationalization of structures

Given ionic radii, calculate the radius ratio, ρ, of a binary compound, and predict which type of structure the compound will have by using a “radius ratio” table.  Exercises:  10, 13

Energetics of ionic bonding

3.11       Lattice enthalpy and the Born-Haber cycle

Given the enthalpy changes of all but one step, determine the missing enthalpy change using a Born-Haber cycle.  Exercises:  15

3.12       Calculation of lattice enthalpies

Given ionic radii, calculate the lattice energy of a binary ionic compound.  (Madelung constants, and other constants will be given.)

3.13       Comparison of experimental and theoretical values

3.14       The Kapustinskii equation—SKIP

3.15       Consequences of lattice enthalpies

Arrange simple ionic compounds in order of increasing lattice energy based on charge and size.  Exercises:  19

Sketch a large cation and a large anion.

Predict which of several compounds would be most soluble in water based on the relative sizes of the cation and anion.  Exercises:  18

Defects and nonstoichiometry—SKIP

3.16       The origins and types of defects

3.17       Nonstoichiometric compounds and solid solutions

The electronic structures of solids—

3.18       Conductivities of inorganic solids

Account for variation in conductivity with temperature in metals.

3.19       Bands formed from overlapping atomic orbitals

Explain what a band is.

Describe how density of states (DOS) varies through a band in three-dimensional materials.

3.20       Semiconduction

Use the concept of the Fermi energy distribution to explain how an intrinsic semiconductor conducts at room temperature.

Sketch the band structure of a p- and an n-type extrinsic semiconductor.  Explain how these materials conduct as the temperature is raised.

Chapter 6, Molecular Symmetry

6.1 Symmetry Operations, Elements and Point Groups

Recognize the five basic symmetry operations.  Exercises:  1, 2, 4.

Given the point group flow chart and a molecule, determine which point group the molecule belongs to.  Exercises:  3.  Problems:  1

6.2  Character Tables

Determine the degeneracy of a representation from its symmetry label. 

Determine the representation that an atomic orbital belongs to from a character table.

6.3  Polar molecules

Use symmetry to determine if a molecule is polar, and along which axis it is polar.

6.4  Chiral molecules

Use symmetry to determine if a molecule is chiral.  Problems:  2, 3

6.5  Molecular vibrations—Skipped

6.6  Symmetry-adapted linear combinations

Construct simple symmetry-adapted linear combinations of atomic orbitals.

6.7  The construction of molecular orbitals

Use a character table to label symmetry-adapted linear combinations of atomic orbitals.

Use a character table to determine which orbitals can mix.  Exercises:  6, 7.