Problem 2
Which of these spheres represents F, which represents Br, and which represents Br-?
Problem 3b
Consider the Mg2+, Cl-, K+, and Se2- ions. The four spheres below represent these four ions, scaled according to ionic size. (b) In terms of size, between which of the spheres would you find the (i) Ca2+ and (ii) S2- ions?
Problem 4
In the following reaction
which sphere represents a metal and which represents a nonmetal?
Problem 6d
Shown below is a qualitative diagram of the atomic orbital energies for an Na atom. The number of orbitals in each subshell is not shown.
(d) A sodium vapor lamp (Figure 7.23) operates by using electricity to excite the highest-energy electron to the next highest-energy level. Light is produced when the excited electron drops back to the lower level. Which two energy levels are involved in this process for the Na atom?
- (a) Evaluate the expressions 2 * 1, 2 * 11 + 32, 2 * 11 + 3 + 52, and 2 * 11 + 3 + 5 + 72. How do the atomic numbers of the noble gases relate to the numbers? (b) What topic discussed in Chapter 6 is the source of the number '2' in the expressions in part (a)?
Problem 9
Problem 10
The prefix eka- comes from the Sanskrit word for 'one.' Mendeleev used this prefix to indicate that the unknown element was one place away from the known element that followed the prefix. For example, eka-silicon, which we now call germanium, is one element below silicon. Mendeleev also predicted the existence of eka-manganese, which was not experimentally confirmed until 1937 because this element is radioactive and does not occur in nature. Based on the periodic table shown in Figure 7.1, what do we now call the element Mendeleev called eka-manganese?
- Moseley’s experiments on X rays emitted from atoms led to the concept of atomic numbers. (a) If arranged in order of increasing atomic mass, which element would come after chlorine? (b) Describe two ways in which the properties of this element differ from the other elements in group 8A.
Problem 12
- Among the elements N, O, P, and S, which element or elements have the smallest effect nuclear charge if we use Equation 7.1 to calculate Zeff? Which element or elements have the largest effective nuclear charge?
Problem 13
Problem 14
Which of the following statements about effective nuclear charge for the outermost valence electron of an atom is incorrect? (i) The effective nuclear charge can be thought of as the true nuclear charge minus a screening constant due to the other electrons in the atom. (ii) Effective nuclear charge increases going left to right across a row of the periodic table. (iii) Valence electrons screen the nuclear charge more effectively than do core electrons. (iv) The effective nuclear charge shows a sudden decrease when we go from the end of one row to the beginning of the next row of the periodic table. (v) The change in effective nuclear charge going down a column of the periodic table is generally less than that going across a row of the periodic table
Problem 15a
Detailed calculations show that the value of Zeff for the outermost electrons in Na and K atoms is 2.51+ and 3.49+, respectively. (a) What value do you estimate for Zeff experienced by the outermost electron in both Na and K by assuming core electrons contribute 1.00 and valence electrons contribute 0.00 to the screening constant?
Problem 15b
Detailed calculations show that the value of Zeff for the outermost electrons in Na and K atoms is 2.51+ and 3.49+, respectively. (b) What values do you estimate for Zeff using Slater’s rules?
Problem 15e
Detailed calculations show that the value of Zeff for the outermost electrons in Na and K atoms is 2.51+ and 3.49+, respectively. (e) Predict Zeff for the outermost electrons in the Rb atom based on the calculations for Na and K.
- Detailed calculations show that the value of Zeff for the outermost electrons in Si and Cl atoms is 4.29+ and 6.12+, respectively. (b) What values do you estimate for Zeff using Slater’s rules? (c) Which approach gives a more accurate estimate of Zeff? (d) Which method of approximation more accurately accounts for the steady increase in Zeff that occurs upon moving left to right across a period? (e) Predict Zeff for a valence electron in P (phosphorus) based on the calculations for Si and Cl.
Problem 16
Problem 16a
Detailed calculations show that the value of Zeff for the outermost electrons in Si and Cl atoms is 4.29+ and 6.12+, respectively. (a) What value do you estimate for Zeff experienced by the outermost electron in both Si and Cl by assuming core electrons contribute 1.00 and valence electrons contribute 0.00 to the screening constant?
- Which will experience the greater effect nuclear charge, the electrons in the n = 2 shell in F or the n = 2 shell in B? Which will be closer to the nucleus?
Problem 17
- Arrange the following atoms in order of increasing effective nuclear charge experienced by the electrons in the n = 2 shell: Be, Br, Na, P, Se.
Problem 18
- Which quantity must be determined experimentally in order to determine the bonding atomic radius of an atom? (a) The distance from the nucleus where the probability of finding an electron goes to zero. (b) The distance between the nuclei of two atoms that are bonded together. (c) The effective nuclear charge of an atom.
Problem 19
Problem 20b
With the exception of helium, the noble gases condense to form solids when they are cooled sufficiently. At temperatures below 83 K, argon forms a close-packed solid whose structure is shown below. (b) Is this value larger or smaller than the bonding atomic radius estimated for argon in Figure 7.7?
Problem 20c
With the exception of helium, the noble gases condense to form solids when they are cooled sufficiently. At temperatures below 83 K, argon forms a close-packed solid whose structure is shown below. (c) Based on this comparison would you say that the atoms are held together by chemical bonds in solid argon?
Problem 21a
Tungsten has the highest melting point of any metal in the periodic table: 3422 °C. The distance between W atoms in tungsten metal is 274 pm. (a) What is the atomic radius of a tungsten atom in this environment? (This radius is called the metallic radius.)
Problem 21b
Tungsten has the highest melting point of any metal in the periodic table: 3422 °C. The distance between W atoms in tungsten metal is 274 pm. (b) If you put tungsten metal under high pressure, predict what would happen to the distance between W atoms.
Problem 22
Which of the following statements about the bonding atomic radii in Figure 7.7 is incorrect? (i) For a given period, the radii of the representative elements generally decrease from left to right across a period. (ii) The radii of the representative elements for the n = 3 period are all larger than those of the corresponding elements in the n = 2 period. (iii) For most of the representative elements, the change in radius from the n = 2 to the n = 3 period is greater than the change in radius from n = 3 to n = 4. (iv) The radii of the transition elements generally increase moving from left to right within a period. (v) The large radii of the Group 1 elements are due to their relatively small effective nuclear charges.
Problem 23
Estimate the As¬I bond length from the data in Figure 7.7 and compare your value to the experimental As ¬I bond length in arsenic triiodide, AsI3, 2.55 Å.
- The experimental Pb¬Cl bond length in lead(II)chloride, PbCl2, is 244 pm. Based on this value and data in Figure 7.7, predict the atomic radius of Pb.
Problem 24
Problem 25
Using only the periodic table, arrange each set of atoms in order from largest to smallest: (a) Ar, As, Kr (b) Cd, Rb, Te (c) F, O, N.
Problem 26
Using only the periodic table, arrange each set of atoms in order of increasing radius: (a) Cs, Se, Te (b) S, Si, Sr (c) P, Po, Pb.
Problem 27a
Identify each statement as true or false: (a) Cations are larger than their corresponding neutral atoms.
Problem 27b
Identify each statement as true or false: (b) Li+ is smaller than Li.
Problem 27c
Identify each statement as true or false: (c) Cl- is bigger than I-.
- Explain the following variations in atomic or ionic radii: (a) I- > I > I+ (b) Ca2+ > Mg2+ > Be2+ (c) Fe > Fe2+ > Fe3+
Problem 28
Ch.7 - Periodic Properties of the Elements