Ch.6-7
The structure of which of the following compounds (CH₄, CO₂, NaCl, O₂) suggests that it has the highest boiling point? A) CH₄ B) CO₂ C) NaCl D) O₂
C) NaCl
Atoms seldom exist as independent particles in nature because... A) as single particles, most atoms have low potential energy B) their electronegativity is much lower when they combine with other atoms C) atoms are more stable when they combine with other atoms D) neutral particles are rare
C) atoms are more stable when they combine with other atoms.
Which of the following properties (electrical conductivity, thermal conductivity, brittleness, ductility) is not explained by metallic bonding? A) electrical conductivity B) thermal conductivity C) brittleness D) ductility
C) brittleness
The salts NaCl and CaCl₂ are... A) are good conductors of electricity B) are positively charged C) are held together by ionic bonds D) Both A and B
C) held together by ionic bonds
Orbitals of equal energy produced by the combination of two or more orbitals on the same atom are called... A) bonding orbitals B) valence orbitals C) hybrid orbitals D) high-energy orbitals
C) hybrid orbitals
If two covalently bonded atoms move closer than a distance of the bond length, the potential energy of the atoms... A) becomes negative B) decreases C) increases D) remains constant
C) increases
Ioni bonds form as a result of the electrostatic attraction between... A) dipoles B) electrons C) ions D) nuclei
C) ions
Compared with the energies of neutral atoms that form the ions, a crystal lattice has... A) zero potential energy B) higher potential energy C) lower potential energy D) equal potential energy
C) lower potential energy
Within a metal, the vacant orbitals in the atoms' outer energy levels... A) repel valence electrons B) attract other metal atoms C) overlap D) diffract light
C) overlap
Bond energy is the energy... A) absorbed as a molecule forms B) change as atoms get closer together C) required to break a chemical bond and form separate, neutral atoms D) of two covalently bonded atoms
C) required to break a chemical bond and form separate, neutral atoms.
What is responsible for the good electrical conductivity of metals? A) the arrangement of metal atoms in separate layers B) the high density of metal atoms in the crystal lattice C) the ability of electrons to move freely about the crystal structure D) the fact that metal atoms contain many orbitals separated by very small energy
C) the ability of electrons to move freely about the crystal structure
The electrons involved in the formation of a covalent bond are... A) transferred from one atom to another B) found only in the s orbitals C) valence electrons D) in filled orbitals
C) valence electrons.
In a crystal of sodium chloride, how many oppositely-charged ions does each Na⁺ and Cl⁻ ion have clustered around it? A) 1 B) 2 C) 4 D) 6
D) 6
Because strong attractive forces hold the layers in an ionic crystal in relatively fixed positions, ionic compounds A) are hard B) are brittle C) are not electrical conductors as solids D) All of the above
D) All of the above
The arrangement of ions within a crystal structure and the strengths of the attractions between them vary with the... A) sizes of the ions B) charges of the ions C) numbers of ions of different charges D) All of the above
D) All of the above
VSEPR theory... A) predicts the shape of some molecules B) is limited to polar molecules C) assumes that pairs of valence electrons surrounding an atom repel each other D) Both A and C
D) Both A and C
Which are the intermolecular forces that can act between non-polar molecules? A) covalent bonds B) hybridization C) hydrogen bonds D) London dispersion forces
D) London dispersion forces
Chemical bonding in metals is... A) the same as ionic bonding B) the same as covalent bonding C) a combination of ionic and covalent bonding D) different from ionic or covalent bonding
D) different from ionic or covalent bonding.
Which is a measure of metallic bond strength? A) electron affinity B) electronegativity C) specific heat capacity D) enthalpy of vaporization
D) enthalpy of vaporization
An ionic compound is not represented by a molecular formula because an ionic compound... A) does not contain bonds B) can form crystalline solids C) has no net charge D) lacks molecules
D) lacks molecules
VSEPR theory predicts that the shape of carbon tetrachloride, CCl₄, is... A) linear B) bent C) trigonal planar D) tetrahedral
D) tetrahedral
In a double covalent bond,... A) one atom has more than eight valence electrons B) one atom loses a pair of electrons C) two atoms share D) two atoms share two pairs of electrons
D) two atoms share two pairs of electrons.
What is the apparent charge on the chlorine atom in the molecule HCl? A) +1 B) -1 C) ∂+ D) ∂-
D) ∂-
Which size of compounds has the greatest bond energy? A) HF; H-F bond length = 92 p, B) I₂; I-I bond length = 266 pm C) Cl₂; Cl-Cl bond length = 199 pm D) HCl; H-Cl bond length = 127 pm
A) HF; H-F bond length = 92 p,
The effects of hydrogen bonding will cause which compound to have the highest boiling point? A) H₂O B) PH₃ C) H₂S D) HCl
A) H₂O
Choose the pair of elements (K-0.8, Br-2.8, N-3.0, S-2.5) that will have the greatest ionic character A) K and N B) K and S C) N and Br D) S and Br
A) K and N
To draw a Lewis structure, it is not necessary to know... A) the length of the bonds B) the types of atoms in the molecules C) the numbers of valence electrons for each atom D) the number of atoms in molecule
A) The length of the bond
Metals are malleable because when struck, one plane of metal atoms... A) can slide past another plane without breaking bonds B) cannot easily move out of the way C) moves in a way that maximizes the repulsive forces within the metal D) bonds to the plane directly beneath it
A) can slide past another plane without breaking bonds.
The measure of an atom's ability to attract electrons is its... A) electronegativity B) polarization C) ionization D) electron affinity
A) electronegativity.
Compared with solid ionic compounds, solid molecular compounds generally... A) have lower melting points B) are more brittle C) are harder D) conduct electricity as liquids
A) have lower melting points.
The shape of molecules that contain only two atoms is... A) linear B) bent C) trigonal planar D) Either A or B
A) linear
The valence electrons in a metallic bond... A) move freely throughout the network of metal atoms B) are held tightly by the most positively charged atoms C) are shared equally between two metal atoms D) continuously move from one energy level to another
A) move freely throughout the network of metal atoms
How many double bonds are in the Lewis structure for hydrogen fluoride, HF? A) none B) one C) two D) three
A) none
When an atom completely gives up its valence electrons to another atom, they form a bond that is considered to be... A) purely ionic B) partially ionic C) polar-covalent D) nonpolar-covalent
A) purely ionic.
Some ionic compounds do not dissolve in water because... A) the attractions between the water molecules and the ions are not as strong as the attractions between the ions B) they are less dense than water and float on the surface C) water is a covalent compound and covalent compound cannot dissolve ionic water D) water molecules cannot fit in the spaces between the ions in the crystal lattice
A) the attractions between the water molecules and the ions are not as strong as the attractions between the ions.
The lewis structure of which of the following compounds (NH₃, BF₃, CCl₄, H₂O) does not follow the octet rule? A) NH₃ B) BF₃ C) CCl₄ D) H₂O
B) BF₃
According to VSEPR theory, which molecule (CO₂, H₂O, CS₂, HF) has a bent shape? A) CO₂ B) H₂O C) CS₂ D) HF
B) H₂O
Which of the following molecules is polar? A) C₂H₂ B) H₂O C) BF₃ D) CO₂
B) H₂O
Which of the following is the result of visible light absorbed by a metal? A) Electrons move to higher energy levels and remain there B) Light at a frequency similar to the absorbed frequency is emitted C) Electrons fill the vacant orbitals D) Light is given off as a line spectrum
B) Light at a frequency similar to the absorbed frequency is emitted.
Choose the pair of elements (Na-0.9, Cl-3.0, O-3.5, H-2.1) that will have the least ionic character. A) Na and Cl B) O and Cl C) H and O D) Na and O
B) O and Cl
The VSEPR formula for a molecule of type AB₂E₂ tells you that the molecule is made up of... A) a central atom A, with two B atoms and two E atoms bonded to it B) a central atom A, with two B atoms bonded to it, and two unshared electron pairs C) a central atom A, with two B atoms bonded to it by two bonding electron pairs D) two central atoms B, with an atom A and two atoms E bonded to it
B) a central atom A, with two B atoms bonded to it, and two unshared electron pairs
The arrangement of valence electrons in a metallic is best described as... A) fixed postions in a lattice B) a sea of free-moving electrons C) concentrated electron density around specific atoms D) electron pairs existing in multiple bonds
B) a sea of free-moving electrons
In general, as you move from right to left across any row of the periodic table, the strength of a metallic bond... A) increases B) decreases C) stays the same D) shows no trend
B) decreases
You can estimate the degree to which a bond between two atoms is ionic or covalent by calculating the... A) distance between the atoms' nuclei B) difference in the atom's electronegativities C) atom's atomic radii D) number of atoms in the compound
B) difference in the atoms' electronegativities.
The energy released when one mole of an ionic crystalline solid is formed from ions in the gas state is known as... A) thermal energy B) lattice energy C) ionization energy D) radiant energy
B) lattice energy.
Atoms that are bonded with an electronegativity difference of 0 to 0.3 are generally considered to be... A) negatively charged compounds B) nonpolar-covalent compounds C) polar-covalent compounds D) ionic compounds
B) nonpolar-covalent compounds.
A charged group of covalently bonded atoms is known as a(n) A) anion B) polyatomic ion C) formula unit D) cation
B) polyatomic ion.
Bond length between two bonded atoms is... A) twice the diameter of the molecular B) the separation at which their potential energy is minimum C) the separation at which the motion of each atom stops D) the sum of the diameters of each of the two overlapping electron clouds
B) the separation at which their potential energy is minimum.
A single covalent bond involves the sharing of... A) only one electron B) two electrons C) three electrons D) a variable number of electrons, which depends on the bonding atoms
B) two electrons
Which of the following is not a resonance structure of SO₃?
The one that doesn't have a full oxygen atom and an incorrect central oxygen atom
