CHAPTER 6 OUTLINE
CHEMICAL NAMES AND FORMULAS
I. Introduction to Chemical Bonding
A. Molecules and Molecular Compounds
1. Molecules -- chemical combination of elements (smallest part of a substance that still has the properties of the substance)
2. Molecular compound -- compounds composed of molecules (bunch of molecules)
a. Usually low melting/boiling points
b. Most are liquid or gas
c. Most are combinations of 2 or more nonmetals
d. Represented by molecules
B. Ions and Ionic Compounds
1. Ions -- atoms or groups of atoms that have a positive or negative charge
a. Form by losing or gaining electrons
b. Metallic atoms form positive ions
1. Called Cations
2. Represented by symbol and charge as superscript after symbol
3. Name does not change from element name
c. Nonmetallic atoms form negative ions
1. Called Anions
2. Represented same as Cations
3. Name is element name with -ide ending (suffix)
2. Ionic compounds -- composed of one cation and one anion
a. Represented by formula units
b. Most are solid
c. Metals combined with Nonmetals
d. High melting/boiling points
II. Representing Chemical Compounds
A. Chemical formulas
1. Shows the kind and number of atoms in smallest whole number ratios
a. Subscripts -- number of atoms
b. Diatomic atoms -- H2, N2, O2, F2, Cl2, Br2, I2
B. Molecular formulas
1. Chemical formulas of a molecular substance
a. Does not show arrangement of atoms
C. Formula Units
1. Lowest whole number ratio of ions in ionic compound
a. Not molecule, collection of ions
D. Law of Definite and Multiple Proportions
1. Law of Definite Proportions -- within a samples of any compound, the masses of the elements are always in the same proportion
2. Law of Multiple Proportions -- when two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in small whole number ratios
III. Ionic Charges
A. Monatomic Ions
1. Ions with one atoms can be determined by their position in the Periodic Table
7A
1A
5A
6A
3A
4A
2A
+1
-1
+2
+3
+/-4
-3
-2
2. Group 0 do not usually form compounds
3. Group 4A usually form molecular compounds
4. Transition metals have multiple charges possible
5. Two methods for naming transition metals
a. Stock name -- uses roman numerals after the element name to represent charge
b. Classical name -- uses a root word an suffix
1. -ous suffix for smaller ion charge
2. -ic suffix for larger ion charge
B. Polyatomic Ions
1. Two or more atoms that behave as one unit with on ionic charge
a. Most end (suffix) with -ite and -ate
1. -ite means one less oxygen than -ate
b. Some exceptions (Ammonia, cyanide, hydroxide)
c. When add hydrogen, then loss one negative charge
IV. Ionic Compounds
A. Writing Formulas for Binary (2 ions) Ionic Compounds
1. Net ionic charge = 0
2. Cation is written first
3. Use crisscross method to balance charges
a. Number of charge is used as subscript on other ion
b. Positive and negative signs are dropped
c. Do not use if ionic charges already cancel
B. Naming Binary Ionic Compounds
1. Work backward from above method
2. Transition metals
a. Need to determine charge first
C. Ternary (3 different atoms) Ionic Compounds
1. Usually one ion is polyatomic
2. Use same method as binary
3. Difference - need to use parenthesis for polyatomic ions if more than one is needed
4. Naming is also the same
a. Use reference table for polyatomic
V. Molecular Compounds and Acids
A. Binary Molecular Compounds
1. Use prefixes to determine number of atoms
Mono-
1
Hexa-
6
2
Di-
Hepta-
7
3
Tri-
Octa-
8
4
Tetra-
Nona-
9
5
Penta-
10
Deca-
a. Second atom ends with -ide suffix
b. Mono is dropped for first atom only
c. Prefixes work for formula and naming
B. Naming Common Acids
1. Anion combined with enough H+ ions to balance charge
a. (We will discuss fully how to name acids in chapter 19, for now be familiar with the common acids on p. 160 in the textbook)
VI. Summary of Naming and Formula Writing
A. Practicing Skills: Follow the Arrows
1. (Refer to pp. 161-162)
Outline based upon:
Matta, M. S., Staley, D. D., Waterman, E. L., & Wilbraham, A. C. (2000). Chemistry, Addison-Wesley. (5th ed.). Menlo Park, CA: Prentice Hall, pp. 133-163
