Chapter 11, The Underlying Reasons for Periodic Trends Video Solutions, Principles of Descriptive Inorganic Chemistry

Problem 1

Describe the main periodic trends of the following from left to right in the periodic table: a. electronegativity; b. radius; c. covalent-bond energy; d. common oxidation numbers. Tell in what blocks of the periodic table (if any) you find "anomalous" countertrends.

Susan Hallstrom

Numerade Educator

06:46

Problem 2

Describe the main periodic trends of the following from top to bottom in the periodic table: a. electronegativity; b. radius; c. covalent-bond energy; d. common oxidation numbers. Tell in what blocks of the periodic table (if any) you find anomalous countertrends.

Susan Hallstrom

Numerade Educator

Problem 3

Go back to Chapter 1 and answer (or reanswer) questions 12 and 13.

Check back soon!

03:46

Problem 4

Without the use of tables, arrange each of the following sets in order of increasing size: a. $\mathrm{Li}, \mathrm{C}, \mathrm{F}, \mathrm{Ne}$;
b. $\mathrm{Be}, \mathrm{Ca}, \mathrm{Ba}, \mathrm{Ra}$;
c. B, Al, Ga, In, Tl;
d. V, Nb, Ta, element 105 .

Megan Lucas

Numerade Educator

02:11

Problem 5

Without the use of tables, arrange each of the following sets in order of increasing Pauling electronegativity: a. $\mathrm{Be}, \mathrm{Mg}, \mathrm{Ca}, \mathrm{Sr}, \mathrm{Ba}$;
b. $\mathrm{Na}, \mathrm{Al}, \mathrm{P}, \mathrm{Cl}, \mathrm{Ar}$;
c. $\mathrm{C}, \mathrm{Si}, \mathrm{Ge}, \mathrm{Sn}, \mathrm{Pb}$;
d. $\mathrm{Cu}, \mathrm{Ag}, \mathrm{Au}$, element below $\mathrm{Au}$.

Lottie Adams

Numerade Educator

01:02

Problem 6

Without the use of tables, arrange each of the following sets in order of increasing covalent-bond energies (increasing stability of covalent bonds).
6.1 The following single bonds: $\mathrm{C}-\mathrm{C}, \mathrm{Si}-\mathrm{Si}, \mathrm{Ge}-\mathrm{Ge}, \mathrm{Sn}-\mathrm{Sn}, \mathrm{Pb}-\mathrm{Pb}$.
6.2 The following single bonds: $\mathrm{Li}-\mathrm{Li}, \mathrm{Be}-\mathrm{Be}, \mathrm{B}-\mathrm{B}, \mathrm{C}-\mathrm{C}$.
6.3 The following Mo-Mo bonds: sigma, delta, pi.

Narayan Hari

Numerade Educator

02:25

Problem 7

Sketch $x y$-plane cross-section diagrams for the following orbitals: a. $4 p_x$; b. $3 s ;$ c. $4 d_{x y}$ d. a pi bond formed from $3 d_{x y}$ orbitals on two atoms; e. two $3 d_{x y}$ orbitals on two atoms overlapping to give negative pi overlap (an antibonding $\pi^*$ orbital). Indicate regions of high electron probability by blue or black shading, nodal planes and spheres by red or penciled dashed lines, and show the positive and negative signs for the wave function. Show the $x$ and $y$ axes.

Ian Lee

Numerade Educator

04:11

Problem 8

Rank the $5 s, 5 p, 5 f, 5 d$, and $5 g$ orbitals in order of increasing: a. penetrating ability; b. shielding ability.

Tracy Tourville

Numerade Educator

04:54

Problem 9

In Figure 11.2 are drawn different pairs of atoms ( $\mathrm{A}$ on the left and $\mathrm{B}$ on the right) with orbitals overlapping. In each case tell whether there is positive, negative, or zero overlap between the orbitals of $A$ and of $B$.

Susan Hallstrom

Numerade Educator

04:54

Problem 10

In Figure 11.9 are drawn different pairs of atoms (A on the left and $B$ on the right) with orbitals overlapping. a. Identify the specific atomic orbital used by each atom in each case. b. In each case tell whether there is positive, negative, or zero overlap between the orbitals of $\mathrm{A}$ and of $\mathrm{B}$. $\mathbf{c}$. For each case in which there is positive overlap, identify the bond that is formed as sigma, delta, or pi.
FIGURE CANT COPY
Figure 11.9

Susan Hallstrom

Numerade Educator

02:54

Problem 11

a. Using Slater's rules, calculate $Z^*$ for a 4 s electron of $\mathrm{Zn}$. b. Using Slater's rules, calculate $Z^*$ for a $3 d$ electron of $\mathrm{Zn}$. c. Calculate $\left\langle r_{\max }\right\rangle$ for these two orbitals of zinc. d. Using $Z^*$ for the 4 s electron and given that the covalent radius of zinc is $121 \mathrm{pm}$, calculate the Allred-Rochow electronegativity of $\mathrm{Zn}$. How do you think this value compares with the Pauling value for $\mathrm{Zn}$ ? If you think that it is either substantially ( $>0.5$ units) higher or substantially lower, explain why this is the case.

Dominador Tan

Numerade Educator

03:49

Problem 12

Identify all elements in the periodic table for which the Pauling and AliredRochow electronegativities differ by more than 0.5 . In what parts of the table do these occur? For the element for which the discrepancy is greatest, use the Pauling electronegativity and its known covalent radius to calculate its "real" $Z^*$. Compare this with $Z^*$ computed using Slater's rules. Are the two values close?

Yongyao Zhou

Numerade Educator

01:03

Problem 13

Let us suppose that you have discovered a new element of atomic number 162, which you choose to name Khalidium (Kh). Assume that the normal order of filling of orbitals still prevails in the cighth period.
13.1 Write the full electron configuration of this element.
13.2 Write the valence-electron configuration of this element and of its +2 ion.
13.3 Note that a new type of orbital is used in Kh that is not used in any known atom. How many nodal planes will there be in a sketch of this type of orbital? How many nodal spheres will there be? Will the electrons in this type of orbital be good or poor at shielding the valence electrons of $\mathrm{Kh}$ ? Will electrons in this type of orbital be good or poor at penetrating the inner orbitals of $\mathrm{Kh}$ ?
13.4 Calculate $Z^*$ for the outermost valence electron of $\mathrm{Kh}$.
13.5 Using an estimated covalent radius of $150 \mathrm{pm}$, calculate the AllredRochow electronegativity of Kh. Do you think that the Pauling electronegativity of $\mathrm{Kh}$ will be higher, lower, or about the same as this value?

Lottie Adams

Numerade Educator

02:02

Problem 14

Suppose that some all-powerful being suddenly decided to change the Schrödinger wave equation. After this change, the energies of electrons in all atoms would depend on the principal quantum number only. Everything else would remain the same.
14.1 Using the new rules, list the order of filling of the $s, p$, and so forth orbitals for the first four values of the principal quantum number.
14.2 Write the electron configuration of nickel under the new rules.
14.3 What ions, if any, would nickel now tend to form? Could it achieve a noble-gas electron configuration by covalent bonding? What would be the nearest noble-gas configuration? Classify nickel now as a metal or nonmetal.
14.4 What would happen to the nickels in your pocket when this change was made? What effect would this have on the economy?

Adriano Chikande

Numerade Educator

07:38

Problem 15

Suppose that the solution to the Schrödinger wave equation were to be changed in one way only: The secondary quantum number / would be allowed to go to as high a value as the principal quantum number. a. Write the order of filling of the eight lowest types of orbitals in an atom. b. Draw a new periodic table showing the arrangement of the first 36 elements. c. Assuming that $n s^2 n p^{\circ}$ remains a noble-gas electron configuration, list the noble gases in your new periodic table. $\mathrm{d}$. If the changeover were made at the stroke of 12 midnight, discuss what would then happen to the water in the world.

Joanna Josey

Numerade Educator

02:54

Problem 16

Suppose that the inner lobes of orbitals were to be abolished, so that the $2 \mathrm{~s}$ orbitals, for example, would lie completely outside the 1 s orbitals of the same atom. a. Explain how this would alter the shielding of orbitals. b. Revise Slater's rules to accommodate this change. c. Use the equations for $\left\langle r_{\max }\right\rangle$ and Allred-Rochow electronegativities to reevaluate these quantities for the second- and third-period elements. d. Discuss any changes in periodic trends that would result.

Dominador Tan

Numerade Educator

05:28

Problem 17

Explain why relativistic effects can cause gold to have both a. a lower oxidation number than either $\mathrm{Ag}$ or $\mathrm{Cu}(-1$ in $\mathrm{CsAu})$, and $\mathbf{b}$. a higher oxidation number than either $\mathrm{Ag}$ or $\mathrm{Cu}\left(+5\right.$ in $\left.\mathrm{AuF}_5\right)$.

Bhumika Jayee

Numerade Educator

01:03

Problem 18

Keeping in mind the effects of relativistic contraction and expansion of orbitals and spin-orbit coupling of $p$ orbitals, list some plausible common oxidation numbers for the elements of the seventh period beyond number 102. What element in this period has the best possibility of showing the hitherto-unknown oxidation number of +9 , and what factor might make this possible?

Lottie Adams

Numerade Educator