Download AP Unit 1 Test Review

AP Unit 1 Test Review
Topics Covered:
Matter & Measurement
Atoms, Molecules, & Ions
Atomic Trends & Periodicity
Bonding: General Concepts
Part I: Multiple Choice (~50%)
1. Which of the following conclusions can be drawn from J. J. Thomson's cathode ray experiments?
(A) Atoms contain electrons.
(B) Practically all the mass of an atom is contained in its nucleus.
(C) Atoms contain protons, neutrons, and electrons.
(D) Atoms have a positively charged nucleus surrounded by an electron cloud.
(E) No two electrons in one atom can have the same four quantum numbers.
2. Use these answers for questions 2 - 5.
(A) 1s2 2s22p5 3s23p5
(B) 1s2 2s22p6 3s23p6
(C) 1s2 2s22p62d10 3s23p6
(D) 1s2 2s22p6 3s23p63d5
(E) 1s2 2s22p6 3s23p63d3 4s2
2. An impossible electronic configuration
3. The ground-state configuration for the atoms of a transition element
4. The ground-state configuration of a negative ion of a halogen
5. The ground-state configuration of a common ion of an alkaline earth element
6. Which of the following sets of quantum numbers (n, l, ml, ms) best describes the valence electron of highest
energy in a ground-state gallium atom (atomic number 31) ?
(A) 4, 0, 0, 1/2
(B) 4, 0, 1, 1/2
(C) 4, 1, 1, 1/2
(D) 4, 1, 2, 1/2
(E) 4, 2, 0, 1/2
7. All of the following statements concerning the characteristics of the halogens are true EXCEPT:
(A) The first ionization energies (potentials) decrease as the atomic numbers of the halogens increase.
(B) Fluorine is the best oxidizing agent.
(C) Fluorine atoms have the smallest radii.
(D) Iodine liberates free bromine from a solution of bromide ion.
(E) Fluorine is the most electronegative of the halogens.
8. Question 8-11 refer to atoms for which the occupied
atomic orbitals shown below.
8. Represents an atom that is chemically unreactive
9. Represents an atom in an excited state
10. Represents an atom that has four valence electrons.
11. Represents an atom of a transition metal.
12. In the periodic table, as the atomic number increases from 11 to 17, what happens to the atomic radius?
(A) It remains constant.
(B) It increases only.
(C) It increases, then decreases.
(D) It decreases only.
(E) It decreases, then increases.
13. The ionization energies for element X are listed in the
Ionization Energies for element X (kJ mol¯1)
table above. On the basis of the data, element X is most
First Second Third Fourth
Five
likely to be
580
1815 2740 11600 14800
(A) Na
(B) Mg
(C) AI
(D) Si
(E) P
14. Molecules that have planar configurations include which of the following?
I. BCl3
II. CHCl3
III. NCl3
(A) I only
(B) III only
(C) I and II only
(D) II and III only
(E) I, II, and III
15. The electron-dot structure (Lewis structure) for which of the following molecules would have two unshared
pairs of electrons on the central atom?
(A) H2S
(B) NH3
(C) CH4
(D) HCN
(E) CO2
16. Which of the following molecules has a dipole moment of zero?
(A) C6H6 (benzene)
(B) NO
(C) SO2
(D) NH3
(E) H2S
17. Questions 17-19 refer to the following diatomic species.
(A) Li2
(B) B2
(C) N2
(D) O2
(E) F2
17. Has the largest bond-dissociation energy
18. Has a bond order of 2
19. Contains 1 sigma (s) and 2 pi (p) bonds
20. Which of the following compounds is ionic and contains both sigma and pi covalent bonds?
(A) Fe(OH)3
(B) HClO
(C) H2S
(D) NO2
(E) NaCN
21. In a molecule in which the central atom exhibits sp3d2 hybrid orbitals, the electron pairs are directed
toward the corners of
(A) a tetrahedron
(B) a square-based pyramid
(C) a trigonal bipyramid
(D) a square
(E) an octahedron
Part II: Free Response (~50%)
Your responses to these questions will be graded on the basis of the accuracy and relevance of the information
cited. Explanations should be clear and well organized. Examples and equations may be included in your
responses where appropriate. Specific answers are preferable to broad, diffuse responses.
1.
Nonmetal
Formula of
Compound
C
N
O
Ne
Si
CF4
NF3
OF2
No
SiF4
Compound
P
S
Ar
PF3
SF2
No
Compound
Some binary compounds that form between fluorine and various nonmetals are listed in the table above. A
student examines the data in the table and poses the following hypothesis: the number of F atoms that will bond
to a nonmetal is always equal to 8 minus the number of valence electrons in the nonmetal atom.
(a) Based on the student’s hypothesis, what should be the formula of the compound that forms between
chlorine and fluorine?
(b) In an attempt to verify the hypothesis, the student researches the fluoride compounds of the other
halogens and finds the formula ClF3 . In the boxes below, draw a complete Lewis electron-dot diagram
for a molecule of ClF3.
(c) Two possible geometric shapes for the ClF3 molecule are trigonal planar and T-shaped. The student does
some research and learns that the molecule has a dipole moment. Which of the two shapes is consistent
with the fact that the ClF3 molecule has a dipole moment? Justify your answer in terms of bond polarity
and molecular structure.
In an attempt to resolve the existence of the ClF3 molecule with the hypothesis stated above, the student
researches the compounds that form between halogens and fluorine, and assembles the following list.
Halogen
Formula (s)
F
F2
Cl
Br
BrF, BrF3, BrF5
I
IF, IF3, IF5, IF7
(d) Based on concepts of atomic structure and periodicity, propose a modification to the student’s previous
hypothesis to account for the compounds that form between halogens and fluorine.
2. Using principles of atomic and molecular structure and the information in the table below, answer the
following questions about atomic fluorine, oxygen, and xenon, as well as some of their compounds.
Atom
First Ionization
Energy (kJ mol-1)
F
1,681.0
O
1,313.9
Xe
?
(a) Write the equation for the ionization of atomic fluorine that requires 1,681.0 kJ mol-1.
(b) Account for the fact that the first ionization energy of atomic fluorine is greater than that of atomic oxygen.
(You must discuss both atoms in your response.)
(c) Predict whether the first ionization energy of atomic xenon is greater than, less than, or equal to the first
ionization energy of atomic fluorine. Justify your prediction.
(d) Xenon can react with oxygen and fluorine to form compounds such as XeO3 and XeF4. In the boxes
provided, draw the complete Lewis electron-dot diagram for each of the molecules represented below.
(e) On the basis of the Lewis electron-dot diagrams you drew for part (d), predict the following:
(i) The geometric shape of the XeO3 molecule
(ii) The hybridization of the valence orbitals of xenon in XeF4
(f) Predict whether the XeO3 molecule is polar or nonpolar. Justify your prediction.
Equation Practice: For each of the following three reactions, in part (i) write a balanced equation for the
reaction and in part (ii) answer the question about the reaction. In part (i), coefficients should be in terms of
lowest whole numbers. Assume that solutions are aqueous unless otherwise indicated. Represent substances in
solutions as ions if the substances are extensively ionized. Omit formulas for any ions or molecules that are
unchanged by the reaction.
1.
(a) A barium nitrate solution and a potassium fluoride solution are combined and a precipitate forms.
(i) Balanced equation:
(ii) If equimolar amounts of barium nitrate and potassium fluoride are combined, which reactant, if any, is
the limiting reactant? Explain.
(b) A piece of cadmium metal is oxidized by adding it to a solution of copper(II) chloride.
(i) Balanced equation:
(ii) List two visible changes that would occur in the reaction container as the reaction is proceeding.
(c) Solid mercury(II) oxide decomposes as it is heated in an open test tube in a fume hood.
(i) Balanced equation:
(ii) After the reaction is complete, is the mass of the material in the test tube greater than, less than, or
equal to the mass of the original sample? Explain.