Review: Naming Covalent (Molecular) Compounds
Covalent compounds
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involve bonding between non-metals
involve sharing (not transfer) of electrons
atoms bonded covalently form molecules
To name covalent (non-metal-nonmetal) compounds:
1. Name the first element in the compound using the name as found on the
periodic table.
2. Name the second element with an –ide ending.
3. Use numerical prefixes to show how many of each atom is present in the
molecule.
*mono is omitted for the name of the first element
Prefix
mono
di
tri
tetra
penta
hexa
hepta
octa
nona
deca
Number of atoms
1
2
3
4
5
6
7
8
9
10
Examples:
P2S5
diphosphorus pentasulfide
CCl4
carbon tetrachloride
Si2Br6
disilicon hexabromide
SI4
sulfur tetraiodide
Some exceptions:
1. Diatomics (elements that always exist as covalently-bonded pairs when they are in their pure form): there
are seven: H2 O2 F2 Br2 I2 N2 Cl2
These diatomics are simply given their elemental name, ex: O2 is called oxygen
2. Very common molecules are generally referred to by their common names:
Ex:
H2O
water
NH3
ammonia
Name the following compounds
1. SO2
sulfur dioxide
2. CO
carbon monoxide
3. ClO2
chlorine dioxide
4. N2O
dinitrogen monoxide
5. P2O5
diphosphorus pentoxide
6. CBr4
carbon tetrabromide
7. N2S5
dinitrogen pentasulfide
8. N2O4
dinitrogen tetraoxide
9. BF3
boron trifluoride
10. SiCl4
silicon tetrachloride
11. IF7
iodine heptafluoride
12. P4O10
tetraphosphorus decaoxide
13. PO3
phosphorus trioxide
14. BrCl3
bromine trichloride
15. P2O4
diphosphorus tetraoxide
16. NF4
nitrogen tetrafluoride
17. S4N4
tetrasulfur tetranitride
18. NF3
nitrogen trifluoride
19. NO2
nitrogen dioxide
20. Cl2O7
dichlorine heptaoxide
Write the formulas for the following compounds:
1. carbon dioxide
CO2
2. nitrogen monoxide
NO
3. nitrogen dioxide
NO2
4. sulfur trioxide
SO3
5. tetraphosphorus decoxide
P4O10
6. tetraphosphorus hexoxide
P4O6
7. iodine monochloride
ICl
8. dihydrogen monoxide
H2O
9. nitrogen trichloride
NCl3
10. carbon disulfide
CS2
11. disilicon hexabromide
Si2Br6
12. tetranitrogen tetrasulfide
N4S4
13. carbon monoxide
CO
14. dinitrogen pentoxide
N2O5
15. water
H2O
16. ammonia
NH3
17. phosphorus pentachloride
PCl5
18. carbon tetrachloride
CCl4
19. diselenium dichloride
Se2Cl2
20. dinitrogen tetroxide
N2O4
Naming Acids
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Acids are a special group of substances, they are compounds of non-metals but they
form ions in solution.
Acids can be recognized by the fact that their chemical formula generally begins with H
Because acids are a unique group, they have different naming rules:
Acid
Example
Anion
Clchloride
NO2nitrite
NO3nitrate
HCl
HNO2
HNO3
Anion
ending
How To Name it
Name
-ide
hydro(stem)ic acid
hydrochloric acid
-ite
(stem)ous acid
nitrous acid
-ate
(stem)ic acid
nitric acid
**Two stem ‘exceptions’:
S
sulfur
– the stem is ‘sulfur’
ex. sulfuric acid
P phosphorus – the stem is ‘phosphor’
ex. phosphoric acid
Examples: Use the rules to name the following:
1. HBr
2. HClO4
3. H2S
hydrobromic acid
perchloric acid
hydrosulfuric acid
Complete the table with the missing acid names or formulas.
Formula
1. HNO3
2. H2SO4
3. H2SO3
4. H2C2H3O2
5. H3PO4
6. H2S
7. H2CO3
8. HClO
9. H2S
10. H2F
Name
nitric acid
sulfuric acid
sulfurous acid
acetic acid
phosphoric acid
hydrosulfuric acid
carbonic acid
hypochlorous acid
hydrosulfuric acid
hydrofluoric acid
So…let’s put this all together!!
When naming or writing chemical formulas, first determine what type of compound you are
dealing with:
Ionic
metal+non-metal/polyatomic
Covalent:
non-metal+non-metal
Acid:
formula begins with H
Type of Chemical Bonds
Classify the following compounds as ionic, covalent, or acids.
1. CaCl2
Ionic
11. MgO
Ionic
2. CO2
Covalent
12. CuCl2
Ionic
3. H2SO4
Acid
13. HCl
Acid
4. BaSO4
Ionic
14. KI
Ionic
5. K2O
Ionic
15. NaOH
Ionic
6. NaF
Ionic
16. NO2
7. Na2CO3
Ionic
17. AlPO4
Ionic
8. CH4
Covalent
18. FeCl3
Ionic
9. SO3
Covalent
19. P2O5
Covalent
Ionic
20. N2O3
Covalent
10. LiBr
Covalent
Naming Practice (all types of compounds)
Name the following compounds:
1. CaCO3
calcium carbonate
2. SCl6
sulfur hexachloride
3. PCl5
phosphorus pentachloride
4. CaS
calcium sulfide
5. Cu2SO3
copper (I) sulphite
6. K3N
potassium nitride
7. NH4NO3
ammonium nitrate
8. Al(OH)3
aluminum hydroxide
9. HNO3 (aq)
nitric acid
10. HBr (aq)
hydrobromic acid
11. N2O4
dinitrogen tetraoxide
12. O2
oxygen
13. Mg3N2
magnesium nitride
14. NF3
nitrogen trifluoride
15. NH3
ammonia
16. H2CO3 (aq)
carbonic acid
17. CS2
carbon disulfide
18. H2S (aq)
hydrosulfuric acid
19. AuCl3
gold (III) fluoride
20. KMnO4
potassium permanganate
Write the formulas of the following compounds:
1. potassium nitrate
KNO3
2. iron (III) chloride
FeCl3
3. acetic acid
HC2H3O2
4. nitrous acid
HNO2
5. nitrogen monoxide
NO
6. zinc phosphate
Zn3(PO4)2
7. hydrochloric acid
HCl
8. tin (IV) chloride
SnCl4
9. magnesium hydride
MgH2
10. nickel (II) chlorate
Ni(ClO3)2
11. diphosphorus pentoxide
P2O5
12. ferric hydroxide
Fe(OH)3
13. phosphoric acid
H3PO4
14. strontium phosphide
Sr3P2
15. sulfur dioxide
SO2
16. aluminum oxide
Al2O3
17. zinc fluoride
ZnF2
18. carbon dioxide
CO2
19. mercury (II) sulfate
HgSO4
20. sulphuric acid
H2SO4