1. 5.3-Compound Names and Formulas
I can:
-use the period table to determine period charge in Groups 1, 2, and 17, including hydrogen and oxygen
-identify a compound using conventional naming systems that include Greek prefixes where appropriate (Prefixes limited to represent values from one to 10)
-identify the formula for a covalent or ionic substance

2. Naming Ionic Compounds
Formed by cations-anions.
Both ions are included in name.
Naming of cations include the elements of which they are composed.
Sodium loses an electron= Na+
Calcium loses two electrons= Ca2+
Aluminum loses three electrons= Al3+
Group 1 ions have 1+ charge, while group 2 has 2+ charge

3. Naming Ionic Compounds, cont.
Names of anions are altered names of elements.
Same group will have same charge
“ide” is placed as suffix
NaF=sodium fluoride

4. Same cation names must show their charge
FeO v. Fe2O3
Both named iron oxide
See the problem?
Transition metals can form several cations with different charges.
Some cation name must be followed by Roman numeral in parentheses.
Fe2O3 = Fe3+, Iron(III) oxide.
now where did the Fe3+ come from?

5. Determining the charge of a transition metal cation.
Total charge must be 0!

6. Writing Formulas for Ionic Compounds
What is the formula for Aluminum Fluoride?
AlF3

7. Naming Covalent Compounds
SiO2 (silicon dioxide) and CO2 (Carbon Dioxide)
Where are they on the periodic table?
Numerical (#’s) prefixes are used to name covalent compounds of two elements
Tells how many atoms of each element
1 atom in first element does not get prefix
Whichever element is further right on periodic table is named second and ends in “ide.”
In other words, start with one that is more metal like.
BF3
Boron trifluoride
N204
Dinitrogen Tetroxide
CO?

8. Chemical Formulas for Covalent Compounds
Mass of each element in compounds must be measured first.
Empirical Formula (simplest): Tells smallest whole-number ratio of atoms that are in compound. (reduced to ratio)
H2O= 2:1 ratio
Problem: compounds can have same empirical formula, but be very different.

10. Molecular formulas are determined from empirical formulas.
Each compound has its own Moleculelar formula: chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of atoms. (actual number)
Look at examples on previous slide.

11. practice
ture.htm