Download Rules for Naming Compounds

Rules for Naming Compounds
1. When combining ions or atoms to form a compound, always write the metal first, then the
nonmetal.


Ions with positive oxidation numbers (+) are considered to be metals.
Ions with negative oxidation numbers (-)are considered to be nonmetals.
ex.
Chart 1 – Metals and Nonmetals
Metal
Nonmetal
Formula
H+1
O-2
H2O
Ba+2
S-2
BaS
NH4
+1
CO3
Ca+2
-2
(NH4)2CO3
F-1
CaF2
2. When naming a compound, the atom representing the metal remains the same; however,
the atom representing the nonmetal is changed by dropping the suffix or ending and
adding –ide.
ex.
Chart 2 – Suffixes for Nonmetals
Metal
Nonmetal
Name
Formula
Hydrogen
Oxygen
Hydrogen oxide
H2O
Barium
Sulfur
Barium sulfide
BaS
Lithium
Iodine
Lithium iodide
LiI
Calcium
Fluorine
Calcium fluoride
CaF2
The exceptions to this rule pertain to polyatomic ions. Do not change the suffix or ending
of the polyatomic ion that represents a nonmetal.
ex.
Metal
Chart 3 – Polyatomic Ions as Nonmetals
Nonmetal
Name
Formula
Cesium
Carbonate
Cesium carbonate
Ce2CO3
Lithium
Sulfate
Lithium sulfate
Li2SO4
Hydrogen
Peroxide
Hydrogen peroxide
H2O2
Strontium
Nitrate
Strontium nitrate
Sr(NO3)2
3. When naming a compound, use Roman Numerals to identify the oxidation state of the
metal, not the nonmetal.


This method is usually used with atoms of multiple oxidation states.
Copper, Tin, Lead, Mercury, and Iron
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
Do not use the Roman numeral with the nonmetal.
ex.
Metal
Cu
+2
Chart 4 – Roman Numerals for Metals
Nonmetal
Name
-2
O
Formula
Copper II Oxide
CuO
Sn+4
O-2
Tin IV Oxide
SnO2
Pb
+4
O2
-2
Lead IV Peroxide
Pb(O2)2
Hg+2
O-2
Mercury II Oxide
HgO
4. When naming a compound, use –ic and –ous suffix to identify the oxidation state of the
metal, not the nonmetal.



This method is usually used with atoms of multiple oxidation states.
Copper, Tin, Lead, Mercury, and Iron
Do not use the –ic and –ous ending as a suffix on the nonmetal.
ex.
Metal
Cu
+2
+4
Chart 5 – The Metals ends :-ic and –ous
Nonmetal
Name
Formula
-2
Cupric Oxide
CuO
-2
O
Sn
O
Stannic Oxide
SnO2
Pb+4
O2-2
Plumbic Peroxide
Pb(O2)2
+2
-2
Mercuric Oxide
HgO
-2
Ferrous Oxide
FeO
Hg
+2
Fe
Atom
O
O
Chart 6 – Summary of Rules 3 and 4
-ic or -ous
Roman Numeral
Chemical Symbol
Copper
Cupric
Copper II
Cu+2
Copper
Cuprous
Copper I
Cu+1
Mercury
Mercuric
Mercury II
Hg+2
Mercury
Mercurous
Mercury I
Hg+1
Iron
Ferric
Iron III
Fe+3
Iron
Ferrous
Iron II
Fe+2
Tin
Stannic
Tin IV
Sn+4
Tin
Stannous
Tin II
Sn+2
Lead
Plumbic
Lead IV
Pb+4
Lead
Plumbous
Lead II
Pb+2
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5. When naming a compound, use the prefixes below to identify the number of atoms in the
metal or nonmetal.
 The prefix can be used with the metal and the nonmetal or with just the metal or with just
the nonmetal.
 The prefix usually identifies the atom in the compound with the subscript
 See charts 7-8
Chart 7 – Prefixes for Compounds
Number
Prefix
1
mono-
2
di-
3
tri-
4
tetra-
5
penta-
6
hexa-
7
hepta-
8
octa-
9
nona-
10
deca-
Chart 8 – Naming Compounds with Prefixes
Chemical Formula
Name
CO2
carbon dioxide
H2O
dihydrogen oxide
CO
carbon monoxide
CCl4
carbon tetrachloride
CS2
carbon disulfide
SF6
sulfur hexafluoride
BaCl2
barium dichloride
NaI
monosodium iodide
6. When metals are combined with oxygen, many compounds are formed depending upon
the oxidation state of the metals.
 -ate
 -ite
 hypo…ite
 hyper…ate
 Roman Numerals are used
 prefixes are used
 See charts 9-10 below
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Chart 9 - Nitrogen Oxides
Chemical Formula
Name
N2O
nitrogen I oxide, dinitrogen oxide, nitrous oxide
NO
nitrogen II oxide, nitrogen oxide, nitric oxide
N2O3
nitrogen III oxide, dinitrogen trioxide
NO2
nitrogen IV oxide, nitrogen dioxide, nitrite
N2O4
nitrogen IV oxide, dinitrogen tetraoxide
N2O5
nitrogen V oxide, dinitrogen pentoxide
Chart 10 – hypo, hyper, -ate, -ite prefixes and suffixes
Chemical Formula
Name
HClO4
hydrogen perchlorate
HClO3
hydrogen chlorate
HClO2
hydrogen chlorite
HClO
hydrogen hypochlorite
H3PO4
hydrogen phosphate
H3PO3
hydrogen phosphite
H3PO2
hydrogen hypophosphite
H2SO4
hydrogen sulfate
H2SO3
hydrogen sulfite
H2SO2
hydrogen hyposulfite
HNO3
hydrogen nitrate
HNO2
hydrogen nitrite
HNO
hydrogen hyponitrite
7. Acids are formed by adding a hydrogen ion to an ionic compound. The subscript (aq) is
added to the compound to designate the compound is an acid.



see Chart 11
(aq) means aqueous or dissolved in water
The hydrogen or hydronium ion is key to forming the acid
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Ion
Chart 11 - Ionic Compounds Forming Acids
+ H+
Compound
Acid
ClO4- (perchlorate)
+ H+
HClO4 (hydrogen perchlorate)
HClO4(aq) (perchloric acid)
ClO3- (chlorate)
+ H+
HClO3 (hydrogen chlorate)
HClO3(aq) (chloric acid)
ClO2- (chlorite)
+ H+
HClO2 (hydrogen chlorite)
HClO2(aq) (chlorous acid)
ClO- (hypochlorite)
+ H+
HClO (hydrogen hypochlorite)
HClO(aq) (hypochlorous acid)
Cl-
+ H+
HCl (hydrogen chloride)
HCl(aq)
C2H3O2- (acetate)
+ H+
HC2H3O2 (hydrogen acetate)
HC2H3O2(aq) (acetic acid)
CO3-2 (carbonate)
+ H+
H2CO3 (hydrogen carbonate)
H2CO3(aq) (carbonic acid)
C2O4-2 (oxalate)
+ H+
HC2O4-2 (hydrogen oxalate)
HC2O4-2(aq) (oxalic acid)
PO4-3 (phosphate)
+ H+
H3PO4 (hydrogen phosphate)
H3PO4(aq) (phosphoric acid)
PO3-3 (phosphite)
+ H+
H3PO3 (hydrogen phosphite)
H3PO3(aq) (phosphorous acid)
PO2-3 (hypophosphite)
+ H+
H3PO2 (hydrogen hypophosphite)
H3PO2(aq) (hypophosphorous acid)
SO4-2 (sulfate)
+ H+
H2SO4 (hydrogen sulfate)
H2SO4(aq) (sulfuric acid)
SO3-2 (sulfite)
+ H+
H2SO3 (hydrogen sulfite)
H2SO3(aq) (sulfurous acid)
SO2-2 (hyposulfite)
+ H+
H2SO2 (hydrogen hyposulfite)
H2SO2(aq) (hyposulfurous acid)
NO3- (nitrate)
+ H+
HNO3 (hydrogen nitrate)
HNO3(aq) (nitric acid)
NO2- (nitrite)
+ H+
HNO2 (hydrogen nitrite)
HNO2(aq) (nitrous acid)
NO- (hyponitrite)
+ H+
HNO (hydrogen hyponitrite)
HNO(aq) (hyponitrous acid)
(chlorine)
(hydrochloric acid)
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Chart 12 - Common Acids
Binary Acids (2 elements)
Monoprotic
Chemical Formula
Acid
HF(aq)
hydrofluoric acid
HCl(aq)
hydrochloric acid
HBr(aq)
hydrobromic acid
HI(aq)
hydroiodic acid
Polyprotic
H2S(aq)
hydrosulfuric acid
Ternary Acids (3 elements)
HNO3(aq)
nitric acid
HNO2(aq)
nitrous acid
H2SO4(aq)
sulfuric acid
H2SO3(aq)
sulfurous acid
HClO4(aq)
perchloric acid
HClO3(aq)
chloric acid
HClO2(aq)
chlorous acid
HClO(aq)
hypochlorous acid
HC2H3O2(aq)
acetic acid
H3PO4(aq)
phosphoric acid
H2CO3(aq)
carbonic acid
H2BO3(aq)
boric acid
8. When naming organic compounds, use the prefix that designates the number of carbons in
the compound.

See chart 13
6
Chart 13 – Prefixes for organic compounds
Number of Carbons
Prefix
1
meth-
2
eth-
3
prop-
4
but-
5
pent-
6
hex-
7
hept-
8
oct-
9
non-
10
dec-
9. When naming organic compounds, use the suffix that designates the number of single
bonds in the compound.




If the compound has all single bonds which cause the compound to be saturated with
hydrogen atoms. The suffix is –ane.
If the compound has all single bonds and 1 double bond, the suffix used is –ene.
If the compound has all single bonds and 1 triple bond, the suffix used is –yne.
See chart 14-17
Chart 14 – Suffixes for organic compounds
Types of Bonds
Suffix
Single Bonds
-ane
Double Bonds
-ene
Triple Bonds
-yne
7
Chart 15 – Suffixes for Saturated Hydrocarbons
Saturated Hydrocarbons
Name
Chemical Formula
methane
CH4
ethane
C2H6
propane
C3H8
butane
C4H10
pentane
C5H12
hexane
C6H14
heptane
C7H16
octane
C8H18
nonane
C9H20
decane
C10H22
equation
CnH2n+2
Chart 16 – Suffixes for Unsaturated Hydrocarbons
Unsaturated Hydrocarbons
Name
Chemical Formula
ethene
C2H4
propene
C3H6
butene
C4H8
pentene
C5H10
hexene
C6H12
heptene
C7H14
octene
C8H16
nonene
C9H18
decene
C10H20
equation
CnH2n
8
Chart 17 – Suffixes for Unsaturated Hydrocarbons
Polyunsaturated Hydrocarbons
Name
Chemical Formula
ethyne
C2H2
propyne
C3H4
butyne
C4H6
pentyne
C5H8
hexyne
C6H10
heptyne
C7H12
octyne
C8H14
nonyne
C9H16
decyne
C10H18
equation
CnH2n-2
9
Chart 18 – Summary of the Hydrocarbons
Name
Chemical Formula
ethyne
C2H2
propyne
C3H4
butyne
C4H6
pentyne
C5H8
hexyne
C6H10
heptyne
C7H12
octyne
C8H14
nonyne
C9H16
decyne
C10H18
equation
CnH2n-2
ethene
C2H4
propene
C3H6
butene
C4H8
pentene
C5H10
hexene
C6H12
heptene
C7H14
octene
C8H16
nonene
C9H18
decene
C10H20
equation
CnH2n
methane
CH4
ethane
C2H6
propane
C3H8
butane
C4H10
pentane
C5H12
hexane
C6H14
heptane
C7H16
octane
C8H18
nonane
C9H20
decane
C10H22
equation
CnH2n+2
10
Structure Formulas for
11
12
Works Cited
Smoot, Robert C., et al. Chemistry A Modern Course. Columbus: Merrill, 1990.
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