1. Lesson 3.2 – Naming Compounds
J. Venables
Northwestern High School
Chemistry 1 Honors

2. Cations formed from a metal have the same name as the metal.
Naming of compounds, nomenclature, is divided into organic compounds (those containing C) and inorganic compounds (the rest of the periodic table).
Cations formed from a metal have the same name as the metal.
Example: Na+ = sodium ion.
If the metal can form more than one cation, then the charge is indicated in parentheses in the name.
Examples: Cu+ = copper(I); Cu2+ = copper(II).
Cations formed from non-metals end in -ium.
Example: NH4+ = ammonium ion.

3. Example: Cl- is ____________.
Negative Ions
Monatomic anions (with only one atom) are called ide.
Example: Cl- is ____________.
Exceptions: hydroxide (OH-), cyanide (CN-), peroxide (O22-).
Polyatomic anions (with many atoms) containing oxygen end in -ate or -ite. (The one with more oxygen is called -ate.) – see sheet.
Examples: NO3- is nitrate, NO2- is _______.

4. Chemical nomenclature is a systematic way of naming compounds.
Name the cation followed by the anion.
For monatomic cations use the element name.
For monatomic anions, use the root element name and the suffix –ide.
To distinguish between different oxidation states of the same element, the oxidation state is written in parentheses after the name of the cation. (no roman numerals for group 1, group 2, Al, Zn, Cd, Ag)
When the compound contains a polyatomic ion, name the cation followed by the name of the polyatomic ion.

5. Naming Ionic Compounds
Name the cation then anion for the ionic compound.
Example: BaBr2 = barium bromide.
Examples – Name each:
Ca(HSO3)2
Ba(ClO3)2
Na3N
Al(CN)3
(NH4)3PO4
LiNO3
Cu(NO2)2

6. Naming Ionic Compounds
Name the cation then anion for the ionic compound.
Example: BaBr2 = barium bromide.
Examples – Name each:
Ca(HSO3)2 calcium hydrogen sulfite
Ba(ClO3)2 barium chlorate
Na3N sodium nitride
Al(CN)3 aluminum cyanide
(NH4)3PO4 ammonium phosphate
LiNO3 lithium nitrate
Cu(NO2)2 copper (II) nitrite

7. Examples of Writing Formulas
Example: barium chlorate = Ba(ClO3)2.
Examples – Write the formula for each:
Ammonium chloride
Potassium carbonate
Aluminum sulfate
Magnesium acetate
Cobalt (III) nitrate
Lead (IV) bromide
Mercury (II) chlorite

8. Examples of Writing Formulas
Example: barium chlorate = Ba(ClO3)2.
Examples – Write the formula for each:
Ammonium chloride NH4Cl
Potassium carbonate K2CO3
Aluminum sulfate Al2(SO4)3
Magnesium acetate Mg(C2H3O2)2
Cobalt (III) nitrate Co(NO3)3
Lead (IV) bromide PbBr4
Mercury (II) chlorite Hg(ClO2)2

9. Naming Binary Molecular (Covalent) Compounds
The first element is always named first using the entire element name.
The second element is named using its root and adding the suffix –ide.
Prefixes are used to indicate the number of atoms of each element in a compound.

10. Examples Dinitrogen tetroxide Sulfur hexafluoride Dihydrogen monoxide
P2O5
XeF4
PF3

11. Examples Dinitrogen tetroxide N2O4 Sulfur hexafluoride SF6
Dihydrogen monoxide H2O
P2O5 diphosphorus pentoxide
XeF4 xenon tetrafluoride
PI3 phosphorus triiodide

12. Names and Formulas for Acids
Acids are compounds that start with hydrogen (H). H is bonded to a negative ion
The names of acids are related to the names of anions:
-ide becomes hydro-….-ic acid;
-ate becomes -ic acid;
-ite becomes -ous acid.

13. Examples
HCl
HNO3
H2SO3
Chlorous acid
Perbromic acid
Hydrosulfuric acid

14. Examples
HCl Hydrochloric acid
HNO3 Nitric acid
H2SO3 Sulfurous acid
Chlorous acid HClO2
Perbromic acid HBrO4
Hydrosulfuric acid H2S