1. Chapter 4 “Chemical Names and Formulas”
H2O
Chapter 4 “Chemical Names and Formulas”
Modified and adapted from
Pre-AP Chemistry
Charles Page High School
Stephen L. Cotton

2. The student will: SWBAT’2
classify the type of bond that forms between two given elements.
write the chemical symbol/name given the name/chemical symbol of an element.
classify a given compound as ionic or molecular.  
given a sheet of common ions, represent an ionic compound in multiple ways--using words and chemical formula.  
represent a molecular compound in multiple ways-- using words, chemical formula and diagrams.  
represent the seven common diatomic molecules in multiple ways-- using words, chemical formula and diagrams.

3. SWBAT Scale
4: Same as a 3.0 but I can make inferences & application to the SWBAT’s
3: I COMPLETELY understand all parts of the SWBAT
2: I understand MOST of the SWBAT’s with teacher help
1: I understand a little of the SWBAT’s but need teacher help
0: I do NOT understand any part of the SWBAT’s and need help!

4. Section 4.3 Naming and Writing Formulas for Molecular Compounds
OBJECTIVES:
Interpret the prefixes in the names of molecular compounds in terms of their chemical formulas.

5. Section 4.3 Naming and Writing Formulas for Molecular Compounds
OBJECTIVES:
Apply the rules for naming and writing formulas for binary molecular compounds.

6. Video
Watch Tyler Dewitt demonstrate how to write names for Molecular Compounds.
Naming Covalent Molecular Compounds

7. Molecular Compounds Compounds where both elements have neg. charges
both elements are from right side
both element are non-metals
electrons are shared, not transferred
they generally have low MP & so can be a S/L/G

8. Molecular compounds are…
made of just nonmetals
smallest piece is a molecule
can’t be held together by opposite charge attraction
can’t use charges to figure out how many of each atom (there are no charges present)

9. Molecular compounds are easier!
Ionic compounds use charges to determine how many of each.
You have to figure out charges.
May need to criss-cross numbers.
Molecular compounds: the name tells you the number of atoms.
Uses prefixes to tell you the exact number of each element present!

10. Molecular Compounds Binary molecule Rules for naming binary molecules
2 atoms w/ covalent bond
Rules for naming binary molecules
1st element has normal name
2nd element has ending changed to -ide
Use prefixes to say how many of each element
Do not use a prefix with the first element if there is only one.
(ex. CO - carbon monoxide)

11. Molecular Naming Prefixes
1 mono 6 hexa
2 di hepta
3 tri octa
4 tetra nona
5 penta deca

12. Prefixes Prefix & name Prefix & name -ide
To write the name, write two words:
Prefix &
name
Prefix &
name
-ide

13. Prefixes
To write the name, write two words:
One exception is we don’t write mono if there is only one of the first element.
Prefix
name
Prefix
name
-ide

14. Prefixes Prefix name Prefix name -ide
To write the name, write two words:
One exception is we don’t write mono if there is only one of the first element.
Normally, we do not have double vowels when writing names (oa oo)
Prefix
name
Prefix
name
-ide

15. Name the compounds
Formula
Name
CO2 CO
PCl3
N2P4
SO4
N2O5
S4Cl9

16. Name the compounds Formula Name CO2 Carbon Dioxide CO Carbon Monoxide
PCl3
Phosphorus Trichloride
N2P4
Dinitrogen Tetraphosphide
SO4
Sulfur Tetroxide
N2O5
Dinitrogen Pentoxide
S4Cl9
Tetrasulfur Nonachloride

17. Write the formulas dinitrogen monoxide phosphourus trichloride
sulfur hexafluroride
carbon disulfide
carbon tetrabromide
dinitrogen tetrahydride
boron trichloride
diphosphourus trioxide
hexaselenium monochloride

18. Write the formulas dinitrogen monoxide N2O
phosphourus trichloride PCl3
sulfur hexafluroride SF6
carbon disulfide CS2
carbon tetrabromide CBr4
dinitrogen tetrahydride N2H4
boron trichloride BCl3
diphosphourus trioxide P2O3
hexaselenium monochloride Se6Cl

19. Molecular Compounds Diatomic molecules
2 of the same nonmetals covalently bonded
are gases
(ex. H2 = hydrogen gas)

20. Yes
PxQy
P=H?
Acid Compound No
>2 Elements?
Yes No
Yes
P=Metal?
2 of Same Elements? No
Yes No
Name Binary Molecule
-use Prefixes
Name Diatomic Molecule

21. Practice by naming these:
= dinitrogen monoxide (also called nitrous oxide or laughing gas)
N2O
NO2
Cl2O7
CBr4
CO2
BaCl2
= nitrogen dioxide
= dichlorine heptoxide
= carbon tetrabromide
= carbon dioxide
(This one will not use prefixes, since it is an ionic compound!)

22. Write formulas for these:
diphosphorus pentoxide
tetraiodine nonoxide
sulfur hexafluoride
nitrogen trioxide
carbon tetrahydride
phosphorus trifluoride
aluminum chloride
(Ionic compound)

23. Answers
P2O5
I4O9
SF6
NO3
CH4
PF3
AlCl3

24. The student will: SWBAT’2
classify the type of bond that forms between two given elements.
write the chemical symbol/name given the name/chemical symbol of an element.
classify a given compound as ionic or molecular.  
given a sheet of common ions, represent an ionic compound in multiple ways--using words and chemical formula.  
represent a molecular compound in multiple ways-- using words, chemical formula and diagrams.  
represent the seven common diatomic molecules in multiple ways-- using words, chemical formula and diagrams.

25. SWBAT Scale
4: Same as a 3.0 but I can make inferences & application to the SWBAT’s
3: I COMPLETELY understand all parts of the SWBAT
2: I understand MOST of the SWBAT’s with teacher help
1: I understand a little of the SWBAT’s but need teacher help
0: I do NOT understand any part of the SWBAT’s and need help!