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Chemistry 1201 Section 4
Spring 1999
Professor Russo
Exam #4
Type of exam: Take-home. You can work with anyone on this exam, including me! You
should know how to do these problems, though. You will probably see similar problems again.
Due: Tuesday, March 9, at the beginning of class.
70 points. Show your work neatly. We will not grade papers that just show an answer,
nor can we assign partial credit if we don't see the work.
________________________________________________________________________
Question #1. Following is a picture of a blank periodic table. Get some highlighters (or
crayons, chalk, water color---I don't care!) and color it in as follows:
1s section:
2s section:
2p section:
3s section:
3p section:
3d section:
4s section:
4p section:
light blue
blue
light red or pink
dark blue
red
yellow
purple
dark red
Question #2. (BLB Text 6.66)
Write complete electron configurations for the following atoms. Use the notation 1s22s2etc.
Do not use any shortcuts (e.g., do not use something like a Krypton core, [Kr]).
a) Al = ____________________________________________________________
b) S = ____________________________________________________________
c) Nd = ___________________________________________________________
d) Y = ____________________________________________________________
Chem 1201 Sec. 4
Exam #4
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Question #3. (based on BLB Text 6.68). Write orbital diagrams for the following elements
and determine the number of unpaired electrons. Here, you should use ABBREVIATED BOX
orbital diagrams and arrows, like this:
Put the BOX structure for Ga in this space
[Kr]
a) Ga
____________
# unpaired electrons
b) Ni
____________
# unpaired electrons
c) Kr
____________
# unpaired electrons
d) Br
____________
# unpaired electrons
Question #4. Why is there a gap in most periodic tables between element 57 (Lanthanum) and
element 72 (Hafnium)? Write the full, unabbreviated electron configurations for each. (Use
1s22s2….notation)
Say why here:
Put the electron configuration of La here; use 1s22s2… form:
Put the electron configuration of Hf here; use 1s22s2… form:
Chem 1201 Sec. 4
Exam #4
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Question #5. (based on BLB 7.12) The concept of atomic size is weird, because the electrons
that determine size do not have exact paths--only clouds. Nevertheless, Ch. 7 of your text
discusses atomic size estimates.
a) Given that a Bi-Br bond is 2.63 Å, use Figure 7.5 to determine the length of a Bi-F bond
(bismuth-fluorine bond).
b) Is the bond covalent or ionic? Defend your answer in the space allowed.
Defend answer in this space only.
c) From left to right across the periodic table, atoms get smaller. Why? Hint: use Coulomb's
law and consider the relative energies of electrons in any given row.
Say why in this space only.
Question #6. (BLB 7.24) First ionization energy generally increases as we go from left to
right across any row of the periodic table, then it jumps to some new level as we go to the next
row. Explain using Coulomb's law and the energies of electrons from one row to the next.
Say why here.
Question #7 (BLB 8.4) Write the Lewis symbol for the following elements or ions:
a) Se
Chem 1201 Sec. 4
b) Al+3
Exam #4
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