This document provides an overview of the general rules for naming compounds in chemistry. It discusses four main rules: 1) For compounds with metals in groups 1, 2, or 13, simply name the elements. 2) For compounds with metals in groups 3-12 or 14-16, include the metal's charge as a Roman numeral in parentheses. 3) For compounds of nonmetals, use prefixes to indicate the number of atoms and designate one element as the cation. 4) For acids containing hydrogen, add prefixes like "hydro" and suffixes like "ic" or "ous" to indicate the anion. Exceptions are made for polyatomic ions which keep their own names.

1. NOMENCLATURE
The Rules of Naming Compounds
Ms. Masterson

2. General Rules of Naming
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A cation if written first and is names first by
simply stating the element’s name
An anion is written second and is named second,
only an –ide ending is added
An exception occurs when a polyatomic ion is
involved
Polyatomic ions keep their own names at ALL
times (see chart in your packet)

3. General Rules of Naming
JUST NAME IT!
ROMAN NUMERALS
PREFIXES
ACIDS

4. RULE 1 - JUST NAME IT!
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If the 1st element is a METAL in groups 1, 2,
or 13
Simply name the elements
The charge on a metal in these groups does
not vary; therefore, there is no need to
specify
JUST simply NAME IT!
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Examples:
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Ca3N2 calcium nitride
GaF3 Gallium fluoride

5. RULE 2 – ROMAN NUMERALS
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If the 1st element is a METAL in groups 3-12
or 14-16
The charge on these atoms vary so it must be
specified in the name
The charge is specified by including roman
numerals in (parentheses) following the
name of the 1st element
Examples:
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AgCl
MnS
silver (I) chloride
Manganese (II) sulfide

6. AgCl
silver (I) chloride
MnS
Manganese (II) sulfide

7. RULE 3 – PREFIXES
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If the 1st element is a NONMETAL
When 2 non-metals bond, one must play the
role of the metal (cation)
You do not need to determine the charge on
the non-metals
These are named by adding prefixes to the
names of both elements to indicate the
NUMBER of atoms of each kind
Examples:
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CO
P2O5
monocarbon monoxide
diphosphorous pentaoxide

9. RULE 4 – ACIDS
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If 1st element is an H
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If H with a halogen (group 17)
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Add “hydro”________”ic acid”
If H with a polyatomic ion
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It’s an acid
ateic
iteous
Examples:
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HCl hydrochloric acid
H2SO4
sulfatesulfuric acid
HNO2
nitritenitrious acid