1. Naming Compounds Ionic Compounds Binary Covalent Compounds

2. Naming Ionic Compounds Rule 1
The cation is written first in the name; the anion is written second in the name. Example: barium oxide BaO cation anion

3. Cations can be metals or polyatomic ions Examples: Na+ sodium ion (metal) NH4+ ammonium ion

4. Polyatomic Ions Polyatomic ions consist of more than one atom
The atoms of a polyatomic ion are covalently bonded, so they stay together as a single, charged unit
Example: NO3- nitrate ion

5. Rule 2
When the formula unit contains two or more of the same polyatomic ion, the polyatomic ion is written in parentheses with the subscript written outside the parentheses. Example: Ca(NO3)2

6. Rule 3
When the cation is a metal ion with a fixed charge, the name of the cation is the same as the element Example: Na+ = sodium When the cation is a metal ion with a variable charge, the charge on the cation is indicated using a Roman numeral, in parentheses, immediately following the name of the cation Example: Fe3+ = iron(III) Fe2+ = iron(II)

7. Anions can be negatively charged elements or polyatomic ions Examples: Cl- negatively charged element PO43- polyatomic anion

8. Rule 4
If the anion is a monatomic ion, the anion is named by adding the suffix -ide to the root of the element name Example: I- = iodide

9. Polyatomic ions which include oxygen in the anion use either the suffix -ate or -ite.
The “ate” suffix contains more oxygen in the anion than one ending in “ite”
Example: sulfate (SO42-)
sulfite (SO32-)

10. Common Polyatomic Ions

12. Learning Check
Name the following ionic compounds: Na2CO3 MgBr2 BaSO4 NH4OH

13. Naming Binary Covalent Compounds
1. The first element is named first, using the element’s name. 2. Second element is named as an Anion (suffix “-ide”) 3. Prefixes are used to denote the number of atoms 4. “Mono” is not used to name the first element

14. Prefixes for Naming Compounds
number indicated
mono- 1
di- 2
tri- 3
tetra- 4
penta- 5
hexa- 6
hepta- 7
octa- 8
nona- 9
deca- 10
Examples:
CO carbon monoxide
N2O dinitrogen oxide
HI hydrogen iodide
CCl4 carbon tetrachloride
P2O5 diphosphorus pentoxide
Prefixes are used for covalent compounds only

15. Learning Check Name the following compounds: PBr3 N2O4 SiCl4 CS2 H2Se