Objectives
 Determine
the name of covalent
compounds
 Determine the formulas of covalent
compounds
Naming Covalent Compounds
 Are
named using
different rules
 For two-element
covalent compounds, we
use numerical prefixes
to tell how many atoms
of each element are in
the molecule
 Example: N2O4
Dinitrogen tetroxide
Practice
 SF4
 PCl3
 N2O
 P2O5
 CCl4
Writing Formulas for Covalent
Compounds
 Step
1: Write down the symbols that
match the element names
 Step 2: Write the value of any prefixes
as the subscript for each corresponding
element
Practice
1. Tetraphosphorus decoxide
2. Selenium monoxide
3. Dioxygen difluoride
4. Sulfur hexafluoride
5. Dihydrogen monoxide
6. Nitrogen trihydride
Chemical Formulas for Covalent
Compounds





A compound’s simplest formula is its empirical
formula
Empirical formulas tell us the smallest wholenumber ratio of atoms that are in a compound
Example: H2O
Different compounds can have the same
empirical formula
So we have to use molecular formulas for
some compounds
Empirical & Molecular Formulas
Finding Molecular Formulas