Chem 121
Spring 2014
EXAM IV
CCBC-Catonsville
Name: _____________________________________
(Thurs 5/1/14)
*** ALWAYS ANSWER IN FULL SENTENCES!
*** On numerical problems, you MUST show your set ups. When dimensional analysis is specified, you MUST set up the problem by dimensional analysis.
*** Use your time wisely. Do not get stuck on one question.
*** Answer each question carefully, with thought and with confidence! Do not stop to check over your work until you have worked through the entire exam.
PAGE
TOTAL
SCORE
YOUR
SCORE
POSSIBLE
1 22
2 19
3 20
4 15
5 24
TOTAL 100
Bonus p.5 4
Adjusted total to Exam IV =
Current Course Total =
(including 4 Exams, 10 Wiley, 4 Paper HW & 14 Quizzes)

Chem 121 EXAM IV Name: _____________________________________
Spring 2014
1. (4 pts) For n = 4, what are the allowed values of quantum number
Page 1 l
? Ans. ______________
How many electrons in an atom can have quantum numbers n =6 and l
= 2? Ans. _____
2. (6 pts) Fill in the electrons for ground state for the V
2+
ion.
E
__ __ __
__ __ __ __ __ 4p
3d __
__ __ __ 4s
3p
__
3s
__ __ __
__ 2p
2s
__
1s
Write the FULL electron configuration for V
2+
on the blank below:
Electron configuration: ____________________________________________________
3. (2 pts) Give the electron configuration of tin USING THE CORE METHOD.
4. (2 pts) Give the electron configuration of ONLY the valence electrons of lead.
5. (2 pts) Give the electron configuration of ONLY the valence electrons of nitride ion.
6. (2 pts) Give the formula of an cation that is isoelectronic with Ca
+2
. Ans. ________
7. (2 pts) Consider ground state tin atom. Circle one: paramagnetic or diamagnetic
8. (2 pts) Give the electron configuration of the electrons that shield the nuclear charge from the outer shell electrons of the bromine atom.

Chem 121
Spring 2014
EXAM IV Name: _____________________________________
Page 2
9. (15 pts) Give the Lewis structure for each of the following. If there are resonance structures, give all of them and then circle the most stable one. Resonance hybrid is not necessary. Remember to include the formal charges. a) Ca(OH)
2 b) XeF
3
+ c) PO
4
3–
10. (4 pts) State the geometry of two of the species in Question #8 above (using conventional terminology) b) XeF
3
+
_____________________ c) PO
4
3–
______________________________
(a) is not required.

Chem 121
Spring 2014
EXAM IV Name: __________________________________
Page 3
11. (4 pts) a) Fill in the formal charges (if any) of the following structures and CIRCLE the most stable structure:
..
..
: : : : b) Are these isomers or are they resonance structures? Circle one: isomers or resonance structures
12. (16 pts) Fill in the blanks for each of the following. You can use the bottom of the page as scratch paper. That section of the page will not be graded.
B
B A
..
B
..
B A B
..
B A B B
..
B
A B
B B hybridization of A: _______________ _______________ _______________ _______________ molec. geometry: _______________ _______________ _______________ _______________
bond angles _______________ _______________ _______________ _______________
Assuming B is more electronegative than A, determine the molecular polarity: polar or nonpolar? _______________ _______________ _______________ _______________

Chem 121
Spring 2014
EXAM IV Name: _____________________________________
Page 4
13. (6 pts) (a) Fill in formal charges (if any) and (b) give the resonance hybrid for the following resonance structures:
H
C
:
..
O :
C
..
H
: O
:
C C
..
:
H H
H H
Resonance hybrid:
14. (5 pts) Consider the structure on the right. a) What is the bond angle of H–O–C? Ans. ____ b) What is the bond angle of O–C=C? Ans. ____ c) What is the bond angle of C–N–H? Ans. ____
..
H
..
..
C N H
H H
15. (4 pts) The anion below is surrounded by 2 water molecules. Draw the Lewis structure of two water molecules showing how they would orient themselves around a bromide ion.
Br
–

Chem 121
Spring 2014
EXAM IV Name: _____________________________________
Page 5
(4 pts each) MULTIPLE CHOICE: CIRCLE the one best answer for each of the following:
16. Which is larger?
A. Ca
2+
B. K
+
C. They are the same in size.
17. Which has the larger magnitude of lattice energy?
A. MgO B. KCl
18. Which is the largest?
A. C B. N
19. Based on which rule is this forbidden? ↑↓ ↑↑ ↑↓
3p
A. Aufbau Principle B. Hund’s rule C. Pauli Exclusion Principle D. Octet Rule
20. Which has the higher ionization energy?
A. nonmetals B. metals
21. Where does the extra large increase in ionization energy occur for the beryllium atom?
A. between the first and second ionization energy.
B. between the second and third ionization energy.
C. between the third and fourth ionization energy.
D. between the fourth and fifth ionization energy.
Bonus Points:
(1 pt) Make sure you have your full name on all pages, front and back.
(3 pts) Draw the structures of 2 water molecules with correct bond angles showing how they would attract each other and with an arrow point to EXACTLY what is broken when we boil water.