AP Chemistry: Unit 2 Practice Questions
Refer to the following diatomic species (A) Li2 (B) B2 (C) N2 (D) O2 (E) F2 Has a bond order of 2
02
The melting point of MgO is higher than that of NaF. Explanations for this observation include which of the following? I. Mg2+ is more positively charged than Na+. II. O2- is more negatively charged than F-. III. The O2- ion is smaller than the F- ion.
1 and 2 only
Which of the following ground-state electron configurations represents the atom that has the lowest first-ionization energy?
3s1
On the basis of the information above, which of the following arranges the binary compounds in order of increasing bond polarity?
CH4 < SiCl4 < SF4
To make Au stronger and harder, it is often alloyed with other metals, such as Cu and Ag. Consider two alloys, one of Au and Cu and one of Au and Ag, each with the same mole fraction of Au. If the Au/Cu alloy is harder than the Au/Ag alloy, then which of the following is the best explanation based on the information in the table above?
Cu atoms are smaller than Ag atoms, thus they interfere more with the displacement of atoms in the alloy.
Which of the following arranges the molecules N2, O2, and F2 in order of their bond enthalpies, from least to greatest?
F2 < O2 < N2
Consider atoms of the following elements. Assume that the atoms are in the ground state. The atom that contains only one electron in the highest occupied energy sublevel
Ga
Which of the following correctly indicates whether the solid represented by the particulate model shown above conducts electricity and explains why or why not?
It does not conduct electricity because its ions cannot move freely within the solid.
Refer to the following diatomic species (A) Li2 (B) B2 (C) N2 (D) O2 (E) F2 Has the largest bond-dissociation energy
N2
Which of the following compounds contains both ionic and covalent bonds?
NH4Cl
The effective nuclear charge experienced by the outermost electron of Na is different than the effective nuclear charge experienced by the outermost electron of Ne. This difference best accounts for which of the following?
Na has a lower first ionization energy than Ne.
Based on the data in the tables above, which of the following statements provides the best prediction for the boiling point of NaCl ?
NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in NaCl than in NaF .
The photoelectron spectra above show the energy required to remove a 1s electron from a nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum?
Nitrogen atoms have a smaller nuclear charge than oxygen atoms.
Silicon crystals are semiconductors. Which of the following is a correct reason for the increase in the conductivity of Si crystals when a small fraction of Si atoms are replaced with those of a different element?
P atoms introduce additional mobile negative charges.
Which of the following scientific claims about the bond in the molecular compound HF is most likely to be true?
The bond is highly polar.
For element X represented above, which of the following is the most likely explanation for the large difference between the second and third ionization energies?
The electron removed during the third ionization is, on average, much closer to the nucleus than the first two electrons removed were.
The table above shows the first ionization energy and atomic radius of several elements. Which of the following best helps to explain the deviation of the first ionization energy of oxygen from the overall trend?
There is repulsion between paired electrons in oxygen's 2p orbitals.
The BF3 molecule is nonpolar, whereas the NF3 molecule is polar. Which of the following statements accounts for the difference in polarity of the two molecules?
Unlike BF3, NF3 has a nonplanar geometry due to an unshared pair of electrons on the N atom.
Consider atoms of the following elements. Assume that the atoms are in the ground state. The atom that contains exactly two unpaired electrons
br
ionic
brittle, large difference in electronegativity
Of the following compounds, which is the most ionic?
cacl2
Which of the following Lewis diagrams represents a molecule that is polar?
cl, cl, h, c
Lewis electron-dot diagrams for CO2 and SO2 are given above. The molecular geometry and polarity of the two substances are
different because S has a greater number of electron domains (regions of electron density) surrounding it than C has
A particle-level diagram of a metallic element is shown above. Typically, metals are both malleable and ductile. The best explanation for these properties is that the electrons involved in bonding among metal atoms are
equally shared and form nondirectional bonds
Two pure elements react to form a compound. One element is an alkali metal, X, and the other element is a halogen, Z. Which of the following is the most valid scientific claim that can be made about the compound?
it contains ionic bonds.
Which of the following complete Lewis diagrams represents a molecule containing a bond angle that is closest to 120°?
largest one
h3no
left
metallic
malleable
Refer to the following diatomic species (A) Li2 (B) B2 (C) N2 (D) O2 (E) F2 Contains 1 sigma (σ) and 2 pi (π) bonds
n2
Which of the following is a nonpolar molecule that contains polar bonds?
nh3
The mass spectrum of the element Sb is most likely represented by which of the following?
number located on periodic table
resonance
polar species
least polar
similarly in electronegativity
The hybridization of the carbon atoms in the molecule represented above can be described as
sp3
Copper atoms and zinc atoms have the same atomic radius, 135 picometers. Based on this information, which of the following diagrams best represents an alloy containing only copper and zinc atoms?
substitutional alloy
The geometry of the SO3 molecule is best described as
trigonal planar
