AP Chemistry – Ch7 HW
Ch7 HW#1 p341 39,43,45,49a,53,Bonus1,Bonus2
39. Microwave radiation has a wavelength around 1.0cm. Calculate the frequency and the energy of a single photon of
this radiation. Calculate the energy of an Avogadro’s number of photons (called an einstein) of this radiation.
43. It takes 7.21 x 10-19 J of energy to remove an electron from an iron atom.
What is the maximum wavelength of light that can do this?
45. Calculate the de Broglie wavelength for:
a. a proton with a velocity 90.% of the speed of light.
49. Calculate the wavelength of light emitted when the following transition occurs in the hydrogen atom.
a. n=3 →n=2
53. Does a photon of visible light (λ ≈ 400nm to 700nm) have sufficient energy to excite an electron in hydrogen atom
from the n=1 to the n=5 energy state?
1. What is the force of attraction between a sodium ion and a chloride ion in a salt crystal, where the distance apart
is 0.94 nm?
2. What is the force of attraction between a barium ion and a chloride ion in a salt crystal, where distance is 1.21 nm?
Ch7 HW#2 p342 50b, 69(1st 4),71
50. Calculate the wavelength of light emitted when the following transition occurs in the hydrogen atom.
b. n=5 → n=4
69. The elements Si, Ga, As, and Ge are all used in the manufacture of various semiconductor devices.
Write the expected electron configuration for these atoms.
Si:
Ga:
As:
Ge:
71. Write the expected electron configurations for each of the following atoms: Sc, Fe, P, Cs, Eu, Pt, Xe, Br.
Ch7 HW#3 p343 85,Bonus1,Bonus2, 97
85. Arrange the atoms in order of increasing first ionization energy.
a. Be, Mg, Ca
b. Te, I, Xe
c. Ga, Ge, In
Bonus 1) The first seven ionization energies for an unknown element
are listed. Which group might this element come from ?
Bonus 2) A table of 1st thru 4th ionization energies is listed
for unknown elements W, X, Y, and Z. Match these letters
with elements Na, Mg, Al, and K, using only a periodic table
and your knowledge of periodic trends.
97. Order the atoms in each of the following sets from the least exothermic electron affinity to the most.
a. S, Se
b. F, Cl, Br, I
Ch7 HW#4 p343 83,87,89 +Bonus
83. Arrange the following groups of atoms in order of increasing size: a. Be, Mg, Ca b. Te, I, Xe
c. Ga, Ge, In
87. In each of the following sets, which atom or ion has the smallest radius?
a. Li, Na, K
b. P, As
c. O+, O, Od. S, Cl, Kr
e. Pd, Ni, Cu
89. In 1994 at an American Chemical Society meeting, it was proposed that element 106 be named seaborgium, Sg,
in honor of Glenn Seaborg, discoverer of the first transuranium element.
a. Write the expected electron configuration for element 106.
b. What other element would be most like element 106 its properties?
c. Write the formula for a possible oxide and a possible oxyanion of element 106.
Bonus1) In each of the following sets, which atom or ion has the smallest radius?
a. Aluminum or the aluminum ion?
b. Bromine or the bromide ion?
c. O2-, F-, Ne, or Na+1?
Ch7 HW#5 p340+ 121,122,123,124,136
121. The successive ionization energies for an unknown element are:
I1 = 896kJ/mol
I2 = 1752 kJ/mol
I3 = 14,807 kJ/mol
I4 = 17948 kJ/mol
To which family in the periodic table does the unknown element most likely belong?
122. An unknown element is a nonmetal and has a valence electron configuration of ns2np4
a) How many valence electrons does this element have?
b) What are some possible identities for this element?
c) What is the formula of the compound this element would form with potassium?
d) Would this element have a larger or smaller radius than barium?
e) Would this element have a greater or smaller ionization energy than fluorine?
123. Elements with very large ionization energies also tend to have highly exothermic electron affinities. Explain.
Which group of elements would you expect to be an exception to this statement?
124. The changes in electron affinity as one goes down a group in the periodic table are not nearly as large
as the variations in the ionization energies. Why?
136. While Mendeleev predicted the existence of several undiscovered elements, he did not predict the existence of
noble gases, the lanthanides, or the actinides. Propose reasons why Mendeleev was not able to predict the
existence of noble gases.
Ch7 Rev p 341 44,47,50,52,54,76(c,d),84,86,88,90,98,102
44. The ionization energy of gold is 890.1 kJ/mol. Is light with a wavelength of 225nm capable of ionizing a gold atom
(removing an electron) in the gas phase.
47. Calculate the de Broglie wavelength of an electron moving with a velocity that is 0.001.c.
50. Calculate the wavelength of light emitted when each of the following transitions occur in the hydrogen atom.
a. n=4 → n=2
b. n=5 → n=4
c. n=5 → n=3
52. Using vertical lines, indicate the transitions from Exercise 50 on an energy-level diagram for the hydrogen atom.
54. An excited hydrogen atom emits light with a frequency of 1.141x1014 Hz to reach the energy level for which n = 4.
In what principal quantum level did the electron begin.
76. Using only the periodic table, write the expected ground-state electron configurations for:
c. an element with three unpaired 5d electrons.
d. the halogen with electrons in the 6p atomic orbitals.
84. Arrange the following groups atoms in order of increasing size: a. Rb, Na, Be
b. Sr, Se, Ne
c. Fe, P, O
86. Arrange the atoms in Exercise 84 in order of increasing first ionization energy.
88. In each of the following sets, which atom or ion has the smallest ionization energy?
a. Cs, Ba, La
b. Zn, Ga, Ge
c. In, P, Ar
d. Tl, Sn, As
e. O, O-, O290. Predict some of the properties of element 117 (the symbol is Uus, following conventions proposed by the
International Union of Pure and applied Chemistry, or IUPAC).
a. What will be its electron configurations?
b. What element will it most resemble chemically?
c. What will be the formula of the neutral binary compounds it forms with sodium, magnesium, carbon and oxygen.
d. What oxyanions would you expect Uus to from?
98. Order the atoms in each of the following sets from the least exothermic electron affinity to the most.
a. N, O, F
b. Al, Si, P
102. Use data in this chapter to determine:
a. the ionization energy of Cl-.
b. the ionization energy of Cl.
+
c. the electron affinity of Cl