Chapter 6 Notes
Chem210FL
page 1
Dr. Lara Baxley
Chapter 6 Notes: Ionic and Molecular Compounds
I. Ions
Learning Goal: Write the symbols for the simple ions of the representative elements
There are two main types of compounds:
•
Ionic:
•
Molecular:
A. Cations and Anions: Losing and Gaining Electrons
Ionic Bond:
Ion:
Cation:
Anion:
Ionic Compound:
B. Determining the Charge on an Ion
•
Atoms lose or gain electrons until they have the same number of electrons as
the nearest noble gas.
Chapter 6 Notes
Chem210FL
page 2
Dr. Lara Baxley
C. Metals with Variable Charges
• Transition metals can form more than one cation, so have to name differently. Can’t use
PT to predict charge.
• Use Roman Numerals to indicate charge on ion.
D. Polyatomic Ions
Polyatomic ion: An ion composed of two or more atoms that are covalently bonded
see last page of these notes for the polyatomic ions that you must know
Practice
1. What is the name of the ClO4– ion?
2. Write the formula for the iodite ion.
II. Writing Formulas for Ionic Compounds
Learning Goal: Write correct formulas for ionic compounds
A. Balancing Charges
Ionic compounds form so that the positive charges of the cations are:
______________________________________________________________
Chapter 6 Notes
Chem210FL
page 3
Dr. Lara Baxley
B. Subscripts
How can you balance the charges between Mg2+ and Cl–?
Practice
1. Write the formula for a compound containing Ca2+ and S2–.
2. What is the formula of a compound containing aluminum ions and oxide ions?
3. What is the correct formula for a compound containing Mg2+ and PO43–?
III. Naming Ionic Compounds
Learning Goal: Communicate with chemical formulas or names of compounds
A. Rules for Naming Ionic Compounds
1. First write the name of the cation.
2. If the cation may have different charges, its charge will be in roman numerals.
3. Leave a space then write the name of the anion
a. if it’s a polyatomic ion, just name it
b. if it’s a monatomic ion (one element) change its ending to –ide.
Practice
1. Name the following compounds.
a. K2CO3
b. MgCl2
c. Cu(ClO4)2
2. Write the formula for iron (III) oxide.
B. Acids (not in Chapter 6)
Acids: _______________________________________________________
Chapter 6 Notes
Chem210FL
page 4
Dr. Lara Baxley
C. Naming Acids (not in Chapter 6)
anion name
acid name
_____ide
becomes
_____ite
becomes
_____ate
becomes
Practice
Name the following acids.
a. HI
b. H2SO4
c. H2S
D. Formulas for Acids (not in Chapter 6)
Examples: H3PO4, HCl, H2SO4, H2S
The number of H’s in the formula is equal to _______________________________
Practice
Write the formulas of the following acids.
a. Hydrobromic acid
b. Iodic acid
c. Carbonic acid
IV. Molecular Compound: Sharing Electrons
Learning Goal: Given the formula of a molecular compound, write its correct name;
given the name of a molecular compound, write its formula.
A. Molecular Compounds
Covalent Bond:
Molecular Compounds:
Chapter 6 Notes
Chem210FL
page 5
Dr. Lara Baxley
B. Diatomic Elements
Diatomic Elements: Elements that exist as molecules with two atoms
B. Naming Covalent Compounds
1. Use Greek prefixes to denote the number of atoms of each element
2. Change the ending of the second element to –ide
3. do not include mono on the first element
Practice #1:
1. Write the formula for the following compounds:
a. silicon tetrachloride
b. tetraphosphorus pentasulfide
2. What is the name of NF3?
Suggested textbook problems:
Ch6: Within Chapter: 1,3,5,7,9,11,13,15,17,19,21,23,25,29,31,33,35,37,41,43,45,49,
51,53,55,57
End of Chapter: 73,75,81,85,89,93,97,101,103,105,107
Chapter 6 Notes
Chem210FL
page 6
Dr. Lara Baxley
Polyatomic Ions
Know These:
Others (used in HW but not tests):
NH4+
ammonium ion
MnO4
hydroxide ion
CrO42
acetate ion
Cr2O72
–
nitrate ion
NO2
–
sulfate ion
SO32
–
phosphate ion
PO33
–
OH
C2H3O2
NO3
–
SO42
PO43
–
CN
–
permanganate ion
–
chromate ion
–
dichromate ion
–
nitrite ion
–
sulfite ion
–
phosphite ion
cyanide ion
–
CO32
HCO3
carbonate ion
–
bicarbonate ion (or hydrogen carbonate ion)
Pattern For Group 7A Oxyanions: polyatomic ions containing Cl, Br, I and 1-4 oxygen atoms
Know these
Example:
-
1 oxygen
hypo__________ite
BrO
hypobromite ion
2 oxygen
______________ite
BrO2
-
bromite ion
3 oxygen
______________ate
BrO3
-
bromate ion
4 oxygen
per ___________ate
BrO4
-
perbromate ion