Chem 100/121
Spring 2004
Exam 2
Name__________________________
Date___________________________
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. Write the correct symbol for the isotope of the element with 24 protons and 28 neutrons:
2 pts
2. Write the correct symbol for a different isotope of the same element as in question 1:
2 pts
3. How many neutrons are present in each of the following:
2 pts
183
70
W:
Ga :
4. How many protons are present in each of the following:
59
27
Co :
2 pts
Al :
Which orbitals are being filled in the block of elements from Sc through Zn?.
3 pts
5 Write the electronic configuration (1s# etc.) for:
10 points
A. F-:______________________________________________________.
B. Na :______________________________________________________
C. C : ______________________________________________________
D. Kr: _________________________________________________________________
E. Ti4+: _________________________________________________________________
6. For each of the following pairs, circle the more electronegative element:
O
B
Rb
Li
P
Cl
N
C
8 pts
7. Rank the following six elements according to the radii of their atoms, from smallest to largest:
Ba, Al, P, Ca, F, Sr
3 pts
Answer:_________________________.
8. How many valence electrons do each of the following atoms have?
8 pts
Mo _______
Y ________
S ________
Rb________
9. Draw the Lewis dot diagram for N2
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) CH2
b) CH3+
c) NO3d) SO2
e) PH3
11. (8 pts) How many electrons must be gained or lost for the following to achieve a noble gas
electron structure?
a. a calcium cation (one positive charge)
b. a nitrogen atom
c. a potassium atom
d. a sulfur anion (one negative charge) ______
12. (2 pts) Element Z reacts with oxygen to form the compound ZO2 and has the lowest fourth
ionization energy of any element in the third 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. K2O
b. NaF
c. Mg3N2
14. Write the formula of the compound that would be formed between the given elements. 4 points
A. Mg and O____________________ B. Cl and K______________________
C. Sc and Se_____________________ D. Be and P_____________________.
15. Give the proper formula for each of the following compounds: (20 pts)
Ferric dichromate
____________________________
Potassium sulfate
____________________________
Calcium phosphite
____________________________
Cupric nitrate
____________________________
Diphosphorus pentoxide ____________________________
Hydroiodic acid
____________________________
Boric acid
____________________________
Cesium carbonate
____________________________
Lithium oxide
____________________________
Potassium hydride
____________________________
16. Give the proper name for each of the following:
Y(NO2)3
____________________________
Ag3N
____________________________
Mg(IO4)2
____________________________
NaMnO4
____________________________
HClO2
____________________________
HgCl2
____________________________
PCl3
____________________________
HCl(aq)
____________________________
BeH2
____________________________
NH3
____________________________
17. Determine the oxidation number of the element underlined.
A. KNO3
B. TiO2
6 points
C. P2O5