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- (b) Using appropriate reference sources, look up the bond lengths of Xe—F bonds in several molecules. How do these numbers compare to the bond lengths calculated from the atomic radii of the elements?
문제 76
문제 77a,b,c
Write a balanced equation for the reaction that occurs in each of the following cases: (a) White phorphrous, P4(s), reacts with chlorine gas. (b) Sodium metal reacts with water. (c) Sulfur reacts with hydrogen gas.
문제 77d
Write a balanced equation for the reaction that occurs in each of the following cases: (d) Fluorine reacts with water.
- Write a balanced equation for the reaction that occurs in each of the following cases: (a) Calcium metal is heated in an atmosphere of oxygen gas. (b) Copper oxide is heated in an atmosphere of hydrogen gas. (c) Chlorine reacts with nitrogen gas. (d) Boron tribromide reacts with water.
문제 78
문제 79
Consider the stable elements through lead (Z = 82). In how many instances are the atomic weights of the elements out of order relative to the atomic numbers of the elements?
문제 80a
Figure 7.4 shows the radial probability distribution functions for the 2s orbitals and 2p orbitals. (a) Which orbital, 2s or 2p, has more electron density close to the nucleus?
문제 80b
Figure 7.4 shows the radial probability distribution functions for the 2s orbitals and 2p orbitals. (b) How would you modify Slater's rules to adjust for the difference in electronic penetration of the nucleus for the 2s and 2p orbitals?
문제 81a
(a) If the core electrons were totally effective at screening the valence electrons and the valence electrons provided no screening for each other, what would be the effective nuclear charge acting on the 3s and 3p valence electrons in P?
문제 81b
(b) Repeat these calculations using Slater’s rules.
문제 81c
(c) Detailed calculations indicate that the effective nuclear charge is 5.6+ for the 3s electrons and 4.9+ for the 3p electrons. Why are the values for the 3s and 3p electrons different?
문제 81d
(d) If you remove a single electron from a P atom, which orbital will it come from?
- As we move across a period of the periodic table, why do the sizes of the transition elements change more gradually than those of the representative elements?
문제 82
- In Table 7.8, the bonding atomic radius of neon is listed as 58 pm, whereas that for xenon is listed as 140 pm. A classmate of yours states that the value for Xe is more realistic than the one for Ne. Is she correct? If so, what is the basis for her statement?
문제 84
문제 85a
The As ¬ As bond length in elemental arsenic is 2.48 Å. The Cl ¬ Cl bond length in Cl2 is 1.99 Å. (a) Based on these data, what is the predicted As ¬ Cl bond length in arsenic trichlo- ride, AsCl3, in which each of the three Cl atoms is bonded to the As atom?
문제 85b
The As ¬ As bond length in elemental arsenic is 2.48 Å. The Cl ¬ Cl bond length in Cl2 is 1.99 Å. (b) What bond length is predicted for AsCl3, using the atomic radii in Figure 7.7?
- The following observations are made about two hypothetical elements A and B: The A¬A and B¬B bond lengths in the elemental forms of A and B are 236 and 194 pm, respectively. A and B react to form the binary compound AB2, which has a linear structure (that is B-A-B = 180°). Based on these statements, predict the separation between the two B nuclei in a molecule of AB2.
문제 86
- Elements in group 17 in the periodic table are called the halogens; elements in group 16 are called the chalcogens. For each of the following periodic properties, state whether the halogens or the chalcogens have larger values: atomic radii, ionic radii of the most common oxidation state, first ionization energy, and second ionization energy.
문제 87
문제 87a
Elements in group 7A in the periodic table are called the halogens; elements in group 6A are called the chalcogens. (a) What is the most common oxidation state of the chalcogens compared to the halogens?
- Note from the following table that there is a significant increase in atomic radius upon moving from Y to La, whereas the radii of Zr to Hf are the same. Suggest an explanation for this effect. Atomic Radii (pm) Sc 170 Ti 160 Y 190 Zr 175 La 207 Hf 175
문제 88
- (a) Which ion is smaller, Co3+ or Co4+? (b) In a lithium-ion battery that is discharging to power a device, for every Li+ that inserts into the lithium cobalt oxide electrode, a Co4+ ion must be reduced to a Co3+ ion to balance charge. Using the CRC Handbook of Chemistry and Physics or other standard reference, find the ionic radii of Li+, Co3+, and Co4+. Order these ions from smallest to largest.
문제 89
문제 89c
(c) Will the lithium cobalt oxide cathode expand or contract as lithium ions are inserted?
문제 89d
(d) Lithium is not nearly as abundant as sodium. If sodium ion batteries were developed that function in the same manner as lithium ion batteries, do you think 'sodium cobalt oxide' would still work as the electrode material? Explain.
문제 90a
The ionic substance strontium oxide, SrO, forms from the reaction of strontium metal with molecular oxygen. The arrangement of the ions in solid SrO is analogous to that in solid NaCl: (a) Write a balanced equation for the formation of SrO(s) from its elements.
문제 90b
The ionic substance strontium oxide, SrO, forms from the reaction of strontium metal with molecular oxygen. The arrangement of the ions in solid SrO is analogous to that in solid NaCl:
(b) Based on the ionic radii in Figure 7.8, predict the length of the side of the cube in the figure (the distance from the center of an atom at one corner to the center of an atom at a neighboring corner).
문제 90c
The ionic substance strontium oxide, SrO, forms from the reaction of strontium metal with molecular oxygen. The arrangement of the ions in solid SrO is analogous to that in solid NaCl:
(c) The density of SrO is 5.10 g>cm3. Given your answer to part (b), how many formula units of SrO are contained in the cube shown here?
문제 91
Explain the variation in the ionization energies of carbon, as displayed in this graph:
문제 93
In the chemical process called electron transfer, an electron is transferred from one atom or molecule to another. (We will talk about electron transfer extensively in Chapter 20.) A simple electron transfer reaction is A(g) + A(g) → A+(g) + A-(g) For a representative nonmetal such as chlorine, is this process exothermic?
문제 94a
(a) Use orbital diagrams to illustrate what happens when an oxygen atom gains two electrons
문제 94b
(b) Why does O3- not exist?
- Use electron configurations to explain the following observations: (a) The first ionization energy of phosphorus is greater than that of sulfur. (b) The electron affinity of nitrogen is lower (less negative) than those of both carbon and oxygen. (c) The second ionization energy of oxygen is greater than the first ionization energy of fluorine. (d) The third ionization energy of manganese is greater than those of both chromium and iron.
문제 95