HOTS Challenge Questions 35 - 60
Name:
Unit 3
Date:
Set One – Basic Anatomy of the Periodic Table
DUE DATE: ___________________________________________
35. In the periodic table, the element hydrogen is sometimes grouped
with the alkali metals and sometimes with the halogens. Explain
why hydrogen resembles the Group 1A AND Group 7A elements.
36. a) What do we mean when we say that two ions or an atom and
an ion are isoelectronic? b) What is wrong with the statement “The
atoms of element X are isoelectronic with the atoms of element Y.”
37. Briefly describe the significance of Mendeleev’s table.
38. Describe the general layout of the modern periodic table.
39. Identify the elements that fit the following descriptions: a) an
alkaline earth metal ion that is isoelectronic with Kr, b) an anion
with a -3 charge that is isoelectronic with K+, c) an ion with a +2
charge that is isoelectronic with Co+3.
40. Which two of the following elements would you expect to show
the greatest similarity in chemical and physical properties: B, Ca, F,
He, Mg, P?
41. Of the elements below, which is the most metallic? How do you
know? Na, Ba, Ca, Cs, or Mg
Set Two – Periodic Trends
DUE DATE: ___________________________________________
42. For each of the following pairs, indicate which one of the two
species is larger: (a) N-3 or F- (b) Mg+2 or Ca+2 (c) Fe+2 or Fe+3
43. Illustrate S-2, Mg+2, F-1, and Na+1. Show their relative sizes.
44. Which ion in the isoelectronic series below has the smallest
radius in a crystal? Explain your choice. O-2, N-3, Na+, Al+3, F-
45. Sodium is much more apt to exist as a cation than is chlorine.
Why? Include as many details about atomic structure and periodic
trends as possible.
46. Which would you expect to experience a greater effective
nuclear charge, a 2p electron of a Ne atom or a 3s electron of a Na
atom? Why?
47. Arrange the following atoms in order of increasing size: P, S, As,
Se.
48. Illustrate the following atoms, and arrange them in order of
decreasing size:
a) Mg2+, Ca2+, Ca.
b) K+, Cl-, Ca+2, S-2.
49. Light can be used to ionize atoms and ions. Which of the
following processes would require shorter wavelength radiation?
Why?
Na (g)  Na+ + eNa+ (g)  Na+2 + e50. The general trend for the first ionization energy is to increase
from left to right across the period. However, the first ionization
energy of aluminum is less than the first ionization energy for Mg.
Give a possible explanation for this exception in the trend.
51. Which of the following ionization energies is the largest? Why?
3rd ionization energy of Al
1st ionization energy of Cs
2nd ionization energy of Ca
1st ionization energy of K
2nd ionization energy of Na
Set Three – Lab Data Analysis
DUE DATE: ___________________________________________
52. Given the following first ionization energies (in units of KJ/mol),
estimate the first ionization energy for magnesium and describe three
different ionization energy trends from the data table that you used
to arrive at your estimate.
Li
Be
B
C
N
O
F
520
899
801
1086
1402
1314
1681
Na
Mg
Al
Si
P
S
Cl
496
?
578
786
1012
1000
1251
53. Using the following boiling point data, estimate the boiling point
of francium:
Metal
Boiling
Point
Li
Na
1347ºC 882.9ºC
K
Rb
Cs
Fr
774ºC
688ºC
678.4ºC
?
54. The first four ionization energies of an element are
approximately 579 KJ/mol, 1980 KJ/mol, 2963 KJ/mol, and 6180
KJ/mol. To which group does this element belong?
Set Four – Chemistry Content Review
DUE DATE: ___________________________________________
55. Ca+2 and Ar are isoelectronic. Why would the PES of Ca+2 differ
from the PES of Ar? Sketch the two graphs to illustrate the
difference.
56. What is the frequency of light in Hz that has a wavelength of
1.23x10-6 cm?
57. The wavelength of a photon that has an energy of 3.7x10-18 J is
________m.
58. Which orbital filling diagram denotes an atom in its ground
state?
a)
b)
c)
d)
e)
59. Lithium has two naturally occurring isotopes: lithium-6 and
lithium-7. If the average atomic mass of lithium is 6.941 amu, what
are the percent abundances of each isotope?
60. A star is estimated to have a mass of 2x1036 kg. Assuming it to
be a sphere of average radius 7x105 km, calculate the average
density of the star in units of grams per cubic centimeter. (Note:
4
volume of a sphere = 𝜋𝑟 3 )
3