CH 12 Smartbook

Which statement correctly explains how polarizability affects intermolecular forces?

A more polarizable molecule experiences stronger dispersion forces and therefore stronger intermolecular forces overall.

Which of the following statements correctly describe dispersion or London forces? Select all that apply.

Dispersion forces are a weak attraction between temporary dipoles. All covalent compounds exhibit dispersion forces.

Which of the following statements correctly describe dipole-dipole forces? Select all that apply.

For two compounds of similar molar mass, the greater the molecular dipole moment, the stronger the dipole-dipole forces. Dipole-dipole forces are the forces of attraction between two polar molecules.

Which of the following statements correctly describe bonding and intermolecular forces? Select all that apply.

Intermolecular forces involve partial or small charges that are far apart and are relatively weak. For a molecular substance, the strength of the intermolecular forces determines the physical properties of its phases. Bonding forces are generally much stronger than intermolecular forces.

______ involve the attraction between an charged particle and a nearby polar molecule. The most common example of such an intermolecular force of attraction is the dissolution of an ionic compound by water.

Ion-dipole forces

Which of the following options correctly reflect the relationship between dispersion forces and particle size? Select all that apply.

Larger particles are more polarizable and experience stronger dispersion forces. For molecules of similar shape, dispersion forces tend to increase with increasing molar mass.

Which option correctly reflects the relationship between molecular shape and the strength of dispersion forces?

Molecules with a large surface area have more points of contact and therefore experience stronger dispersion forces.

Which of the following structural features would allow a molecular substance to exhibit hydrogen bonding between its molecules? Select all that apply.

One or more O-H bonds One or more N-H bonds

Which of the following statements correctly describe the different packing arrangements observed for cubic unit cells? Select all that apply.

The cubic close-packed structure has the repeating pattern abcabc. In hexagonal closest packing, the particles of the third layer lie directly over the particles of the first layer. Cubic closest packing is based on the face-centered cubic cell.

Which of the following statements correctly describe the three types of cubic unit cells? Select all that apply.

The face-centered cubic cell has no particles in the center of the cube. The body-centered cubic unit cell has 2 atoms per unit cell. Each particle in a simple cubic unit cell has a coordination number of 6.

Which of the following options correctly defines polarizability?

This is a measure of how the electron cloud around an atom responds to its electronic environment.

Molecular orbital (MO) theory proposes that metals bond through the formation of extremely large numbers of MOs whose energies are so close that they form a "band" of MOs. The lower energy MOs form the valence band and are occupied by valence electrons. In metallic solids, the empty ______ lies ______ above the valence band at higher energy.

conduction band; directly

The number of nearest neighbors for a particle (atoms or ions) in the unit cell of a crystal is called the _____ number of the particle.

coordination

Bonding forces include ionic bonds, metallic bonds, and ___ bonds. These types of forces are much ___ than the forces of attraction between individual molecules, which are called ___ forces.

covalent stronger intermolecular

Half the distance between the nuclei of two covalently bonded atoms is the ______, whereas half the shortest distance between the nuclei of identical nonbonded atoms is the ______.

covalent radius; van der Waals radius

Solids that have well-defined shapes due to the orderly arrangement of their particles are called ___ solids, whereas solids whose particles lack orderly placement and therefore have poorly defined shapes are ___ solids.

crystalline amorphous

The attraction between an ion and a nearby polar molecule is called an ion -____ interaction. This attractive force is important when a(n) ___ compound dissolves in a polar solvent such as H2O.

dipole ionic

All particles experience ___ forces, a weak attraction that results from induced electron cloud distortion. These forces increase the overall attraction between particles. The more polarizable a particle is, the ___ this effect will be.

dispersion stronger

True or false: A bond between O and H within any molecule is called a hydrogen bond.

f

True or false: Dispersion forces are exhibited only by nonpolar molecules.

f

The larger a molecule or atom, the _____ the number of electrons and the _____ polarizable it will generally be. The strength of the dispersion forces for a particular substance therefore generally _____ as molar mass increases, providing molecules of similar shape are compared.

greater; more; increases

A momentary change in the electron density surrounding an atom or a molecule causes it to have a(n) ___ dipole even if it is not normally polar. This induces a similar effect in a nearby molecule or atom, and there will be a weak attraction between the two particles as a result. These weak interactions are called ___ forces or London forces.

induced dispersion

The particles in a crystal are arranged in an orderly 3-D array called the crystal ___. The simplest repeating unit of the crystal is called the unit ___.

lattice cell

Molecules with a larger surface area have _____ points of contact between them than molecules with less surface area. This leads to _____ dispersion forces overall.

more; stronger

When two polar molecules are close to each other they will orient themselves so that the positive pole of one molecule attracts the ___ pole on the adjacent molecule. These intermolecular forces are called ___ - ___ forces.

negative dipole dipole

When hydrogen is covalently bonded to ___, oxygen, or fluorine there will be an attraction between such a hydrogen and a(n) ___ pair of electrons on a nitrogen, oxygen, or fluorine atom on an adjacent molecule. This attraction is called a(n) ___ bond, and it is the strongest type of intermolecular force between neutral species.

nitrogen lone hydrogen

Dispersion forces are the only type of intermolecular force exhibited by atoms and by ___ molecules. Without the existence of dispersion forces, such substances could not exist in the ___ states of matter.

nonpolar condensed

The term _____ is used to describe how well the electron cloud around an atom responds to changes in its electronic environment.

polarizability

Amorphous solids often form from the rapid cooling of molten crystalline solids because ______.

recrystallization cannot occur quickly enough

According to MO band theory, metals bond by forming a large number of ___ MOs whose energies are so close that they form a continuous band. The lower energy MOs, occupied by the valence electrons, form the ___ band, whereas the empty higher energy MOs form the ___ band.

shared valence conduction

True or false: A compound containing one or more oxygen atoms is not necessarily capable of forming hydrogen bonds between its molecules.

t

True or false: Many amorphous solids are formed from rapid cooling of molten crystals.

t