AP Chemistry Final Review Unit 1&2
Based on periodic trends and the data in the table above, which of the following are the most probable values of the atomic radius and the first ionization energy for potassium, respectively?
242 pm, 419 kJ/mol Potassium is larger than calcium because it has a smaller effective nuclear charge. Because potassium is larger, less energy is required to remove an electron from it than is required to remove an electron from calcium.
Which of the following properties generally decreases across the periodic table from sodium to chlorine?
Atomic radius
Atoms of Mg combine with atoms of F to form a compound. Atoms of which of the following elements combine with atoms of F in the same ratio?
Ba
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?
Being the same size, copper atoms and zinc atoms would form a substitutional alloy in which the atoms substitute for one another in a lattice of positive cores immersed in a sea of electrons.
(A) Cs(B) Ag(C) Pb(D) Br(E) Se Has the highest electronegativity
Br
A 23.0g sample of a compound contains 12.0g of C, 3.0g of H, and 8.0g of O. Which of the following is the empirical formula of the compound?
C2H6O
The photoelectron spectra of the 1s electrons of two isoelectronic species, Ca2+ and Ar, are shown above. Which of the following correctly identifies the species associated with peak X and provides a valid justification?
Ca2+, because its nucleus has two more protons than the nucleus of Ar has
A) Cs(B) Ag(C) Pb(D) Br(E) Se Has the lowest first-ionization energy
Cs
Which of the following best helps to account for the fact that the F- ion is smaller than the O2- ion?
F- has a larger nuclear charge than O2- has.
The question refers to the following species. (A) H2O (B) NH3 (C) BH3 (D) CH4 (E) SiH4 Has two lone pairs of electron
H2O
The percentage of silver in a solid sample is determined gravimetrically by converting the silver to Ag+(aq) and precipitating it as silver chloride. Failure to do which of the following could cause errors in the analysis? Account for the mass of the weighing paper when determining the mass of the sample Measure the temperature during the precipitation reaction Wash the precipitate Heat the AgCl precipitate to constant mass
I, III, and IV
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. In the solid state, the ions are held by strong coulombic forces in fixed positions within the lattice; thus they cannot move or migrate through the lattice.
According to the information in the table above, a 1.00 g sample of which of the following contains the greatest mass of oxygen?
MgO
Which of the following elements has the largest first ionization energy?
N
has molecules with pyramidal shape
NH3
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.
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.
A sample containing atoms of C and F was analyzed using x-ray photoelectron spectroscopy. The portion of the spectrum showing the 1s peaks for atoms of the two elements is shown above. Which of the following correctly identifies the 1s peak for the F atoms and provides an appropriate explanation?
Peak X, because F has a greater nuclear charge than C has.
How many protons, neutrons, and electrons are in an 56/26 F atom?
Protons 26 Neutrons 30 Electrons 26
A compound contains 30. percent sulfur and 70. percent fluorine by mass. The empirical formula of the compound is
SF4
Refer to the following gaseous molecules: (A) BeCl2 (B) SO2 (C) N2 (D) O2 (E) F2 Is a polar molecule
SO2
Refer to the following gaseous molecules: (A) BeCl2 (B) SO2 (C) N2 (D) O2 (E) F2 Is best represented by two or more resonance forms
SO2
Three substances were studied in the laboratory, and the data in the table above were collected. Based on the data, which of the following shows the type of bonding in each substance?
Substance X-Network covalent Substance Y-Metallic Substance Z- Ionic
The mass spectrum of element X is presented in the diagram above. Based on the spectrum, which of the following can be concluded about element X?
The atomic mass of X is between 90 and 92.
Which of the following correctly compares periodic properties of two elements and provides an accurate explanation for that difference?
The atomic radius of Cl is smaller than that of S because Cl has a larger nuclear charge than S does.
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. Fluorine is the most electronegative element, and the difference between the electronegativities of HH and FF is relatively large, resulting in a bond that is highly polar.
Which of the following complete Lewis diagrams represents a molecule containing a bond angle that is closest to 120°?
The carbon atom attached to the oxygen atoms exhibits sp2sp2 hybridization, thus the bond angles around it are close to 120. Another explanation is, the carbon atom attached to the two oxygen atoms is surrounded by three electron domains, which, according to VSEPR theory, will repel one another to produce a trigonal planar geometry around that atom.
After completing an experiment to determine gravimetrically the percentage of water in a hydrate, a student reported a value of 38 percent. The correct value for the percentage of water in the hydrate is 51 percent. Which of the following is the most likely explanation for this difference?
The dehydrated sample absorbed moisture after heating
The particle-level diagram above represents the structure of solid KF. Although the molar mass of KCl is greater than that of KF, the density of KCl is actually less than that of KF. Which of the following representations of the structure of KCl best helps to explain this phenomenon?
The diagram shows that the chloride ions are larger than the fluoride ions, which causes the interionic distances in the solid to increase to the point where the effect of the larger spacing among ions in KCL is greater than the effect of the larger mass of the chlorine on the density.
A sample of a solid labeled as NaCl may be impure. A student analyzes the sample and determines that it contains 75 percent chlorine by mass. Pure NaCl(s) contains 61 percent chlorine by mass. Which of the following statements is consistent with the data?
The sample contains NaCl(s) and LiCl(s).
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 mass spectrum of an average sample of a pure element is shown in the figure above. Which of the following is the identity of the element?
Zr
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 In metals, electrons are free to move as described by the electron sea model. Electrons are shared equally among atoms, and the structure is based on simple close-packed structures that contain no fixed directional bonds.
(A) Cs(B) Ag(C) Pb(D) Br(E) Se Has the largest atomic radius
Cs
What is the identity of the metal chloride?
KCl