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Chem 100/121
Exam 2
You may use a calculator for this exam. The conversion table from the back of the book is included
on the last page of the exam, and you may use the periodic table posted in the room.
1. A. In what ways are isotopes alike?
2 points
B. In what ways are they different?
2 points
2. How many neutrons are present in each of the following:
Sn :
2 pts
Zr :
3 List the electron sublevels from 1s through 5s in order of increasing energy.
3 points
5 Write the electronic configuration (1s# etc.) for:
10 points
A. Br-:______________________________________________________.
B. K+ :______________________________________________________
C. N : ______________________________________________________
D. Ar: _________________________________________________________________
E. Mg: _________________________________________________________________
6. For each of the following pairs, circle the more electronegative element:
8 pts
7. Rank the following five elements according to the radii of their atoms, from smallest to largest:
K, Cs, F, B, Ca, N
3 pts
8. How many valence electrons do each of the following atoms have?
8 pts
As _______
Si ________
O ________
Li ________
9. Draw the Lewis dot diagram for CO2
4 pts
10. (10 pts) Use VSEPR theory to predict the geometry of the central atom in each of the
following (your answer should be one of the following: linear, triangular planar, triangular
planar/bent, tetrahedral, tetrahedral/triangular pyramidal, or tetrahedral/bent)
a) H3O+
b) CH4
c) BH3
d) BeH2
e) NH3
11. (8 pts) How many electrons must be gained or lost for the following to achieve a noble gas
electron structure?
a. a chloride anion
b. a phosphorus atom
c. a lithium atom
d. a magnesium atom ______
12. (2 pts) Element Z reacts with oxygen to form the compound Z2O3 and is a member of the
fourth period of the periodic table. Identify this element.
13. (6 pts) Use Lewis structures and arrows to show the electron transfer that enables these ionic
compounds to be formed:
a. MgO
b. NaBr
c. SiH4
14. Write the formula of the compound that would be formed between the given elements. 4 points
A. Ca and N____________________ B. Sr and O______________________
C. Y and S_____________________ D. Mg and Cl_____________________.
15. Name the following binary compounds:
A. Al2S3_______________________ B. N2O5_________________________
C. S2Cl2_______________________ D. NiS___________________________
2 points
16. Write formulas for the following binary compounds:
4 points
A. Iron(III) sulfide_________________
B. Titanium(III) oxide_________________
C. Lead (II) fluoride______________
D. Copper (II) phosphide_________________.
17. Name each of the following
4 points
A. CaCO3 ___________________________ B. Li2SO4 _________________________
C. K2Cr2O7___________________________D. Ca(MnO4)2 ________________________
18. Write formulas for the following:
6 points
A. Sulfuric acid ______________________ B. Hydrochloric acid _________________
E. Cupric bromide ____________________ F. Titanous chloride ___________________
I. Lithium iodate _____________________ J. Mercurous sulfate _______________
19. Name the following:
4 points
A. HNO3(aq) ___________________________ B. HClO (aq) _________________________
C. H O ____________________________ D. HClO (aq) ________________________
20. Determine the oxidation number of the element underlined.
A. H2SO4
B. MnO2
C. Ca3(PO4)2
D. Co2(NO3)6
8 points