Name: _Lala_Gasparyan_
Date: ____5/18/13____
Section 9.3 Naming and Writing Formulas for Molecular Compounds
Practice Problems
1. Describe how to write the formula for a binary molecular compound.
Use the Prefixes in the name to tell you the subscript of each element in the
formula. Then write the correct symbol for the two elements with appropriate
subscripts.
2. What information do prefixes in the name of a binary molecular compound tell you
about the composition of the compound?
A prefix in the name of a binary molecular compound tells how many atoms of an
element are present in each molecule of the compound
3. Name these molecular compounds.
a. CS2 -carbon disulfide
b. Cl2O7 -dichlorine heptaoxide
c. NCl3 -nitrogen trichloride
4. Write the formulas for these binary molecular compounds.
a. phosphorus pentachloride -PCl5
b. diphosphorus trioxide
-P2O3
c. carbon tetrabromide
-CBr4
5. What type of elements are binary molecular compounds composed of?
Nonmetal, not ions
6. What prefix indicates each of the following numbers of atoms in the formula of a
molecular compound?
a.
b.
c.
d.
e.
3 -tri
5 -penta
1 -mono
8 -octa
4 –tetra
7. When is the prefix mono- omitted?
When the first element of the compound only has one atom
8. Name the following molecular compounds.
a. N2O4 -dinitrogen tetraoxide
b. BCl3 -boron trichloride
c. SO3 -sulfur trioxide
9. The name a student gives for the molecular compound SCl4 is monosulfur
tetrachloride. Is this name correct? Explain.
No, because mono- is supposed to be omitted for the first element
10. What prefix indicates each of the following numbers of atoms in the formula of a
molecular compound?
a.
b.
c.
d.
e.
4 -tetra
6 -hexa
2 -di
10 -deca
9 -nona