Chemistry Chapter 6 Review

What are shared in a covalent bond? a. ions b. Lewis structures c. electrons d. dipoles

C. electrons

A bond that is less than 5% is considered a. polar covalent. b. ionic. c. nonpolar covalent. d. metallic.

C. nonpolar covalent.

Multiple covalent bonds may occur in atoms that contain carbon, nitrogen, or a. chlorine. b. hydrogen. c. oxygen. d. helium.

C. oxygen.

Most chemical bonds are a. purely ionic. b. purely covalent. c. partly ionic and partly covalent. d. metallic.

C. partly ionic and partly covalent.

The concept that electrostatic repulsion between electron pairs surrounding an atom causes these pairs to be separated as far as possible is the foundation of a. VSEPR theory. b. the hybridization model. c. the electron-sea model. d. Lewis theory.

a. VSEPR theory.

When a polar molecule attracts the electron in a non polar molecule, a. a dipole is induced. b. a crystal lattice forms. c. an ionic bond forms. d. a Lewis structure forms.

a. a dipole is induced.

What group of elements satisfies the octet rule without forming compounds? a. halogen b. noble gas c. alkali metal d. alkaline-earth metal

b. noble gas

Bonding in molecules or ions that cannot be correctly represented by a single Lewis structure is a. polyatomic. b. resonance. c. single bonding. d. double bonding.

b. resonance.

Chemists once theorized that a molecule that contains a single bond and a double bond split its time existing as one of these two structures. This effect became known as a. alternation. b. resonance. c. multiple bonding. d. single-double bonding.

b. resonance.

Shifting the layers of an ionic crystal causes the crystal to a. be drawn into a wire. b. shatter. c. become metallic. d. emit light.

b. shatter.

The greater the electronegativity difference between two bonded atoms, the greater the percentage of ___ in the bond. a. ionic character b. covalent character c. metallic character d. electron sharing

A. ionic character

If two covalently bonded atoms are identical, the bond is a. nonpolar covalent. b. polar covalent. c. dipole covalent. d. coordinate covalent.

A. nonpolar covalent.

The percentage ionic character and the type of bond in Br2 (electronegativity for Br is 2.8) is a. 0%; nonpolar covalent. b. 100%; polar covalent. c. 0% pure ionic. d. 100%; pure ionic.

A. 0%; nonpolar covalent.

The electrostatic attraction between positively charged nuclei and negatively charged electrons permits two atoms to be held together by a(n) a. chemical bond. b. London force. c. neutron. d. ion.

A. chemical bond.

In the three molecules, O2, HCl, and F2, what atom would have a partial negative charge? a. oxygen b. hydrogen c. chlorine d. fluorine

C. chlorine

Nonpolar covalent bonds are not common because a. one atom usually attracts electrons more strongly that the other. b. ions always form when atoms join. c. the electrons usually remain equally distant from both atoms. d. dipoles are rare in nature.

A. one atom usually attracts electrons more strongly that the other.

When atoms share electrons, the electrical attraction of an atom for the shared electrons is called the atom's a. electron affinity. b. electronegativity. c. resonance. d. hybridization.

B. electronegativity.

The B--F bond in BF3 (electronegativity for B is 2.0; electronegativity for Br is 2.8) is a. polar covalent. b. ionic. c. nonpolar covalent. d. metallic.

B. ionic

If the atoms that share electrons have an unequal attraction for the electrons, the bond is called a. nonpolar. b. polar. c. ionic. d. dipolar.

B. polar.

The substance whose Lewis structure shows three covalent bonds is a. H²O. b. CH²Cl². c. NH³. d. CCl4.

C. NH³.

A mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together is called a(n) a. dipole. b. Lewis structure. c. chemical bond. d. London force.

C. chemical bond.

The pair of elements that forms a bond with the least ionic character is a. Na and Cl b. K and Cl c. O and Cl d. Mg and Cl

D. Mg and Cl

A neutral group of atoms held together by covalent bonds is a a. molecular formula. b. chemical formula. c. polyatomic ion. d. molecule.

D. molecule

The electrons involved in the formation of a chemical bond are called a. dipoles. b. s electrons. c. Lewis electrons. d. valence electrons.

D. valence electrons.

Differentiate between an ionic compound and a molecular compound.

Ionic compound is composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal. Molecular compound is a chemical compound whose simplest units are molecules.

Explain why metals are good conductors of electricity.

Metals are good conductors of electricity because they have mobile valence electrons. Electrons in the current replace the electrons leaving the metal.

Explain why scientists use resonance structures to represent some molecules.

Resonance structures show the average and neither of the structures accuracy represent that besides resonance.

Bond length is the average distance between two bonded atoms a. at which potential energy is at a minimum. b. at which kinetic energy is at a maximum. c. at which potential energy is at a maximum. d. and equal to one half the diameter of the electron cloud.

a. at which potential energy is at a minimum.

The strong forces of attraction between the positive and negative regions of molecules are called a. dipole-dipole forces. b. London forces. c. lattice forces. d. orbital forces.

a. dipole-dipole forces.

What is placed between a molecule's resonance structures to indicate resonance? a. double-headed arrow b. single-headed arrow c. series of dots d. Lewis structure

a. double-headed arrow

The shiny appearance of a metal is most closely related to the metal's a. highly mobile valence electrons. b. covalent bonds. c. brittle crystalline structure. d. positive ions.

a. highly mobile valence electrons.

Which of the following shows the types and numbers of atoms joined in a single molecule of a molecular compound? a. molecular formula b. potential energy diagram c. covalent bond d. ionic bond

a. molecular formula

A formula that shows only the types and numbers of atoms combined in a single molecule is called a(n) a. molecular formula. b. ionic formula. c. Lewis structure. d. covalent formula.

a. molecular formula.

To draw a Lewis structure, one must know the a. number of valence electrons in each atom. b. atomic mass of each atom. c. bond length of each atom. d. ionization energy of each atom.

a. number of valence electrons in each atom.

In a crystal, the electrons of adjacent ions a. repel each other. b. attract each other. c. neutralize each other. d. have no effect on each other.

a. repel each other.

Compared with nonmetals, the number of valence electrons in metals is generally a. smaller. b. greater. c. about the same. d. almost triple.

a. smaller.

The lattice energy is a measure of the a. strength of an ionic bond. b. strength of a metallic bond. c. strength of a covalent bond. d. net charge on a crystal.

a. strength of an ionic bond.

Which best explains the observation that metals are malleable and ionic crystals are brittle? a. their chemical bonds b. their London forces c. their enthalpies of vaporization d. their net change

a. their chemical bonds

Compared with molecular bonds, the strength of intermolecular forces is a. weaker. b. stronger. c. about the same. d. too variable to compare.

a. weaker.

The electron configuration of nitrogen is 1s²2s²2p³. How many more electrons does nitrogen need to satisfy the octet rule? a. 1 b. 3 c. 5 d. 8

b. 3

How many electrons must be shown in the Lewis structure of the hydroxide ion, OH-? a. 1 b. 8 c. 9 d. 10

b. 8

Which of the following is not an example of a molecular formula? a. H2O b. B c. NH3 d. O2

b. B

A polar molecule contains a. ions. b. a region of positive charge and a region of negative charge. c. only London forces. d. no bonds.

b. a region of positive charge and a region of negative charge.

To appear shiny, a material must be able to a. form crystals. b. absorb and re-emit light of many wavelengths. c. absorb light and change it all to energy as heat. d. change light to electricity.

b. absorb and re-emit light of many wavelengths.

In metals, the valence electrons a. are attached to particular positive ions. b. are shared by all of the atoms. c. are immobile. d. form covalent bonds.

b. are shared by all of the atoms.

Dipole-dipole forces are considered the most important forces in polar substances because the London dispersion forces present in polar substances a. are no longer present. b. are usually much weaker than the dipole-dipole forces. c. are too unpredictable. d. act only in solids.

b. are usually much weaker than the dipole-dipole forces.

Ionic compounds are brittle because the strong attractive forces a. allow the layers to shift easily. b. cause the compound to vaporize easily. c. keep the surface dull. d. hold the layers in relatively fixed positions.

b. cause the compound to vaporize easily.

The equal but opposite charges present in the two regions of a polar molecule create a(n) a. electron sea. b. dipole. c. crystal lattice. d. ionic bond.

b. dipole.

In metallic bonds, the mobile electrons surrounding the positive ions are called a(n) a. Lewis structure. b. electron sea. c. electron cloud. d. dipole.

b. electron sea.

If a material can be shaped or extended by physical pressure, such as hammering, which property does the material have? a. conductivity b. malleability c. ductility d. luster

b. malleability

The properties of both ionic and molecular compounds are related to the a. lattice energies of the compounds. b. strengths of attraction between the particles in the compounds. c. number of covalent bonds each contains. d. mobile electrons that they contain.

b. strengths of attraction between the particles in the compounds.

VSEPR theory is a model for predicting a. the strength of metallic bonds. b. the shape of molecules. c. lattice energy values. d. ionization energy.

b. the shape of molecules.

How many extra electrons are in the Lewis structure of the phosphate ion, PO4^3-? a. 0 b. 2 c. 3 d. 4

c. 3

In a molecule of fluorine, the two shared electrons give each fluorine atom how many electron(s) in the outer energy level? a. 1 b. 2 c. 8 d. 32

c. 8

In drawing a Lewis structure, each nonmetal atom except hydrogen should be surrounded by a. 2 electrons. b. 4 electrons. c. 8 electrons. d. 10 electrons.

c. 8 electrons

Metals are malleable because the metallic bonding a. holds the layers of ions in rigid positions. b. maximizes the repulsive forces within the metal. c. allows one plane of ions to slide past another. d. is easily broken.

c. allows one plane of ions to slide past another.

After drawing a Lewis structure, one should a. determine the number of each type of atom in the molecule. b. add unshared pairs of electrons around nonmetal atoms. c. confirm that the total number of valence electrons used equals the number available. d. determine the electronegativity of each atom.

c. confirm that the total number of valence electrons used equals the number available.

Compared with ionic compounds, molecular compounds a. have higher boiling points. b. are brittle. c. have lower melting points. d. are harder.

c. have lower melting points.

The mixing of two or more atomic orbitals of similar energies on the same atom to produce new orbitals of equal energies is called a. VSEPR theory. b. malleability. c. hybridization. d. dipole-dipole interaction.

c. hybridization.

The energy released when 1 mol of an ionic crystalline compound is formed from gaseous ions is called the a. bond energy b. potential energy c. lattice energy d. energy of crystallization.

c. lattice energy.

The chemical formula for an ionic compound represents the a. number of atoms in each molecule. b. number of ions in each molecule. c. ration of the combined ions present in a sample. d. total number of ions in the crystal lattice.

c. ration of the combined ions present in a sample.

What is the correct Lewis structure for hydrogen chloride, HCl? a. A b. B c. C d. D

d. D

As light strikes the surface of a metal, the electrons in the electron sea a. allow the light to pass through. b. become attached to particular positive ions. c. fall to lower energy levels. d. absorb and re-emit the light.

d. absorb and re-emit the light.

The ions in most ionic compounds are organized into a a. molecule. b. Lewis structure. c. polyatomic ion. d. crystal.

d. crystal.

The reason the boiling point of water (H2O) is higher than the booking point of hydrogen sulfide (H2S) is partially explained by a. London forces. b. covalent bonding. c. ionic bonding. d. hydrogen bonding.

d. hydrogen bonding.

In drawing a Lewis structure, the central atom is generally the a. atom with the greatest mass. b. atom with the highest atomic number. c. atom with the fewest electrons. d. least electronegative atom.

d. least electronegative atom.

A chemical bond formed by the attraction between positive ions and surrounding mobile electrons is a(n) a. nonpolar covalent bond. b. ionic bond. c. polar covalent bond. d. metallic bond.

d. metallic bond.

Malleability and ductility are characteristic of substances with a. covalent bonds. b. ionic bonds. c. Lewis structures. d. metallic bonds.

d. metallic bonds.

The chemical formula for water, a covalent compound, is H2O. This formula is an example of a(n) a. formula unit. b. Lewis structure. c. ionic formula. d. molecular formula.

d. molecular formula.

The forces of attraction between molecules in a molecular compound are a. stronger than the forces among formula units in ionic bonding. b. weaker than the forces among formula units in ionic bonding. c. approximately equal to the forces among formula units in ionic bonding. d. zero

d. zero