Naming Chemical Compounds

Ionic and Molecular

Ionic and Covalent Compounds

Binary Compounds 2 elements

Ionic Compounds a metal and a non-metal a metal and a polyatomic ion ammonium ion and a non-metal ammonium ion and a polyatomic ion

Covalent/Molecular Compounds Two non-metals

Ionic Formulas

Write each ion, cation first. Don’t show charges in the final formula.

Overall charge must equal zero. If charges cancel, just write symbols. If not, use subscripts to balance charges.

Use parentheses to show more than one polyatomic ion.

Stock System - Roman numerals indicate the ion’s charge.

Ionic Naming

Write the names of both ions, cation first.

Change ending of monatomic ions to -ide.

Polyatomic ions have special names.

Stock System - Use Roman numerals to show the ion’s charge if more than one is possible. Overall charge must equal zero.

Example: KCl = Potassium chloride

Ionic Naming

Consider the following: Does it contain a polyatomic ion?

-ide, 2 elements no -ate, -ite, 3+ elements yes

Does it contain a Roman numeral? Check the table for metals not in Groups 1 or 2.

No prefixes!

Name the following binary ionic compounds:

MgBr2

NaF Al2O3

CdO ZnS Na2O K3N

Some metals have more than one oxidation number and when you name them you must indicate which of the oxidation numbers you are using.

There are only 5 elements which you need to memorize which have more than one oxidation number and they are:

Iron Fe (+3 or +2) Lead Pb (+4 or +2) Tin Sn (+4 or +2) Mercury Hg (+2 or +1) Copper Cu (+2 or +1) Nickel Ni ( +2 or +3) Cobalt Co (+2 or +3) Chromium Cr (+2 or +3)

Molecular Nomenclature

Prefix System (binary compounds)

1. Less e-neg atom comes first.

2. Add prefixes to indicate # of atoms. Omit mono- prefix on first element.

3. Change the ending of the second element to -ide.

PREFIXmono-di-tri-tetra-penta-hexa-hepta-octa-nona-deca-

NUMBER123456789

10

Molecular Nomenclature

Naming Compounds

Example: name the following molecular compounds

CO2

N2O3

Cl2O

SO3

CO

N O F

Cl

Br

I

H

Molecular Nomenclature

The Seven Diatomic Elements

Br2 I2 N2 Cl2 H2 O2 F2