CE CHEMISTRY EXAM 4 REVIEW #2 KEY
1. How can a Magnesium atom achieve a noble gas configuration? Losing 2 electrons
2. Write the electron configuration of each of the following and circle any with Noble Gas
configuration:
a. Cl 1s2 2s2 2p6 3s23p5
b. O- 1s2 2s2 2p5
c. Br- 1s2 2s2 2p6 3s23p6 4s2 3d10 4p6 noble gas config.
d. Ca2+ 1s2 2s2 2p6 3s23p6 noble gas config
3. The Alkaline Earth metals form ions with what charge? Do they gain or lose electrons? How many?
2+, they lose 2 electrons
4. How can elements in group VIA achieve a noble gas configuration? Gain 2 electrons
5. Write the formula for the Ionic compound that forms between calcium and sulfur. Does calcium or
sulfur donate electrons? How many? CaS, Calcium donates 2 electrons
6. What is the name of MgO? Magnesium oxide
7. Describe how the atoms that make up an Ionic compound are arranged. Ionic compounds form a
crystal lattice structure
8. Describe what a polar molecule is. A covalently bonded molecule with the electrons being shared
unevenly.
9. What happens within the atom during a covalent bond? Electrons are being shared
10. Write the formula and name of the compounds formed between these elements.
Sodium
Oxygen
Formula
Na2O
Strontium
Chlorine
SrCl2
Carbon
2 Oxygens
CO2
2 phospohorus
4 iodines
P2I4
Name
Sodium oxide
Strontium chloride
Carbon dioxide
Diphosphorus
tetraiodide
11. When Fluorine and Carbon form a compound, describe what is happening with the electrons to
make them form a bond? Electrons are being shared
12. What electronic changes will cause these elements to form a noble gas configuration?
a. Fluorine gain 1 electron
b. Nitrogen gain 3 electron
c. Calcium lose 2 electrons
d. Aluminum lose 3 electrons
13. Determine the type of bond, ionic, polar covalent or non-polar covalent in each of the following
a. KCl ionic
d. AlP ionic
b. CO2 polar covalent
e. FeH ionic
c. H2O polar covalent
14. Draw the Lewis structure of the following elements
a. Br
(BROMINE LOOKS JUST LIKE THIS ONLY Br instead of Cl
b. C
c. Mg
d. He
15. Draw the following Lewis Structures, determine shape, polar bonds and polarity of the molecules.
Molecule
Lewis Structure
Shape
Polar
Polarity of
bonds?
molecule
CO2
Linear
Yes
Nonpolar
H2S
Bent
Yes
Polar
SiH4
Tetrahedral
Yes
Nonpolar
C2H6
Tetrahedral
Yes
around each C
nonpolar
16. Describe a lattice structure and tell which type of bonds/compounds form lattice structures. A
crystal in which many ions of opposite charge occupy lattice sites in a rigid three-dimensional
arrangement called a crystal lattice.
17. Describe a lattice site. A specific place in the crystal lattice, a specific ion
18. What is the difference in an ionic bond and a covalent bond? Ionic compounds are formed from
ions that have gained or lost electrons. Covalent bonds are formed because atoms share electrons
to have a full valence shell
19. What is the trend for electronegativity? Which element has the highest electronegativity?
Electronegativity increases across the period and decreases down a column. Fluorine is the most
electronegative element.
20. Fill in the table:
Name of compound
Formula
Ammonium hydroxide
NH4OH
Dihydrogen Selenide
H2Se
Fe2(CrO4)3
Iron (III) chromate
Barium oxalate
BaC2O4
K3PO4
Potassium phosphate
21. What is a simple ion? An atom that has a positive or negative charge
22. Write the interparticle forces in order of increasing melting points.
Covalent, dispersion, ionic, dipole-dipole
dispersion, dipole-dipole, ionic, Covalent (NETWORK)
I thought this might help to remember the increasing
strength of the interparticle forces. Remember the stronger
the force of attraction the more difficult to loosen, resulting
in higher melting and boiling points.
23. Arrange the following bonds in order of increasing bond polarity.
C-P, C-C, C-F, C-N, C-O
C-C < C-P < C-N < C-O < C-F
24. What is the formula mass of the compound formed between Magnesium and Bromine?
MgBr2 184.113 g/mol
25. What is the formula mass of the compound formed between Aluminum and Sulfate?
Al2(SO4)3 342.15 g/mol