1. NOMENCLATURE
OF COVALENT
COMPOUNDS

2. Theory
Compounds are composed of two or more elements chemically combined. An alternative way to describe a compound is that they contain two or more different kinds of atoms. Binary compounds contain only two types of atoms. The names of all binary compounds always end in “-ide”. If a binary compound contain two different non-metallic elements, then prefixes are used to indicate the number of atoms. The stock system is used to name binary compounds that contain a metal and a non-metal. The next lesson will deal with the stock system.

3. The periodic chart below has the metals highlighted in magenta while the non-metals and the Noble gases are highlighted in green. Note that hydrogen is listed with both the metals and the non-metals.

4. mono- 1 hepta- 7 di- 2 octa- 8 tri- 3 nona- 9 tetra- 4 deca- 10
In order to be effective in using prefixes to name compounds containing two non-metals, these prefixes must be committed to memory:
mono hepta
di octa
tri nona
tetra deca
penta undeca- 11
hexa dodeca- 12

5. When naming compounds using prefixes
remember the formulas are written just like the names and the names just like the formulas. The only difference is that the prefixes in the name are written as subscripts in the formula. Also remember that when there is only one of the first atom a prefix is not used.

6. Example #1-Names to Formulas
I’m a Binary Compound
Sulfur trioxide
1. Write symbols of elements S O 1 3
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

7. Example #2-Names to Formulas
I’m a Binary Compound
dichlorine heptaoxide
1. Write symbols of elements Cl O 2 7
2. Write number of atoms
Final Formula

8. Example #3-Names to Formulas
I’m a Binary Compound
oxygen difluoride
1. Write symbols of elements O F 1 2
2. Write number of atoms
If no prefix, then 1 is
implied and not written
Final Formula

9. Example #4-Names to Formulas
I’m a Binary Compound
dinitrogen tetraoxide
1. Write symbols of elements N O 2 4
2. Write number of atoms
Final Formula

10. Example #5-Names to Formulas
I’m a Binary Compound
phosphorus pentachloride
1. Write symbols of elements P Cl 1 5
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

11. Example #6-Names to Formulas
I’m a Binary Compound
dinitrogen monoxide
1. Write symbols of elements N O 2 1
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

12. Example #7-Names to Formulas
I’m a Binary Compound
carbon monoxide
1. Write symbols of elements C O 1 1
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

13. Example #8-Names to Formulas
I’m a Binary Compound
sulfur hexafluoride
1. Write symbols of elements S F 1 6
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

14. Example #9-Names to Formulas
I’m a Binary Compound
silicon dioxide
1. Write symbols of elements Si O 1 2
2. Write number of atoms
If no prefix, then 1 is implied and not written
Final Formula

15. Example #10-Names to Formulas
I’m a Binary Compound
dinitrogen trisulfide
1. Write symbols of elements N S 2 3
2. Write number of atoms
Final Formula

16. Examples #1- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
CCl4
mono
carbon
tetra
chlor
ide
ine
If first prefix is mono, it is implied and not written
Final Name

17. Examples #2- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
XeF3
mono
xenon
tri
fluor
ide
ine
If first prefix is mono, it is implied and not written
Final Name

18. Examples #3- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
CO2
mono
carbon di ox
ide
ygen
If first prefix is mono, it is implied and not written
Final Name

19. Examples #4- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
AsI3
mono
arsenic
tri
iod
ide
ine
If first prefix is mono, it is implied and not written
Final Name

20. Examples #5- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
P4O6
tetra
phosphorus
hexa ox
ygen
ide
Final Name

21. Examples #6- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
IF5
mono
iodine
penta
fluor
ide
ine
If first prefix is mono, it is implied and not written
Final Name

22. Examples #7- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
XeO3
mono
xenon
tri ox
ide
ygen
If first prefix is mono, it is implied and not written
Final Name

23. Examples #8- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
N2S5 di
nitrogen
penta
sulf
ide ur
Final Name

24. Examples #9- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
SiCl4
mono
silicon
tetra
chlor
ide
ine
If first prefix is mono, it is implied and not written
Final Name

25. Examples #10- Formulas to Names
1. Write names of elements
2. Write number of atoms
I’m a Binary Compound
NI3
mono
nitrogen
tri
iod
ide
ine
If first prefix is mono, it is implied and not written
Final Name

26. Practice Problems
By now you should have an idea of what is expected when naming covalent binary compounds using prefixes.
In order to master this naming system you need to practice until you feel proficient in naming compounds using prefixes.

27. Practice Problem #1 No, "Cl" is not carbon & iodine, see element list
ClF3
Choose the correct name for the compound
1. carbon iodine trifluoride
No, "Cl" is not carbon & iodine, see element list
2. chlorine trifluorine
No, all binary compounds end with "ide"
3. chlorine trifluoride
Very good, click arrow to continue
4. chlorine tetrafluoride
No, you need to review prefixes
5. none of the above
No, there is a correct answer
next problem
Element List
Prefixes

28. Practice Problem #2 Very good, click arrow to continue
arsenic pentabromide
Choose the correct formula for the compound
1. AsBr5
Very good, click arrow to continue
2. ArBr5
No, "Ar" is not correct, see element list
3. AsBr7
No, you need to review prefixes
4. As5Br
No, the subscript is with the wrong element
5. none of the above
No, there is a correct answer
next problem
Element List
Prefixes

29. Practice Problem #3 No, you need to use more prefixes
Choose the correct name for the compound
1. nitrogen trioxide
No, you need to use more prefixes
2. dinitride trioxide
No, only the last element ends with "ide"
3. dinitrogen trioxygen
No, all binary compounds end in "ide"
4. dinitrogen trioxide
Very good, click arrow to continue
5. none of the above
No, there is a correct answer
next problem
Prefixes

30. Practice Problem #4 No, you have too many subscripts
carbon disulfide
Choose the correct formula for the compound
1. C2S2
No, you have too many subscripts
2. C2S
No, the subscript is with the wrong element
3. CSi2
No, "Si" is not correct, see element list
4. CS2
Very good, click arrow to continue
5. none of the above
No, there is a correct answer
next problem
Element List

31. Practice Problem #5 No, you need to review prefixes
Si3O9
Choose the correct name for the compound
1. trisilicon heptaoxide
No, you need to review prefixes
2. trisilicon nonaoxide
Very good, click arrow to continue
3. trisilicon decaoxide
No, you need to review prefixes
4. silicon nonaoxide
No, you need more prefixes
5. none of the above
No, there is a correct answer
next problem
Prefixes

32. Practice Problem #6 No, you don't have any subscripts
dichlorine monoxide
Choose the correct formula for the compound
1. ClO
No, you don't have any subscripts
2. Cl2O
Very good, click arrow to continue
3. ClO2
No, you have the wrong subscripts
4. Cl2O2
No, you have the wrong subscripts
5. none of the above
No, there is a correct answer
next problem
Prefixes

33. Practice Problem #7 No, you do not use "mono" for the first element
SeF6
Choose the correct name for the compound
1. monoselenium hexafluoride
No, you do not use "mono" for the first element
2. silicon hexafluoride
No, "Se" is not silicon, see element list
3. selenium hexafluorine
No, all binary compounds end with "ide"
4. Selenium tetrafluoride
No, you need to review prefixes
5. none of the above
Very good, click arrow to continue
next problem
This is selenium hexafluoride
Element List
Prefixes

34. Tetraphosphorus decaoxide
Practice Problem #8
Tetraphosphorus decaoxide
Choose the correct formula for the compound
1. P4O10
Very good, click arrow to continue
P6O10
No, you have the wrong subscripts
PO10
No, this says that there are 4 molecules
4. P2O5
No, you have the wrong subscripts
5. none of the above
No, there is a correct answer
next problem
Prefixes

35. Practice Problem #9 No, write the name in the same order as formula
NF3
Choose the correct name for the compound
1. trifluorine nitride
No, write the name in the same order as formula
2. mononitrogen trifluoride
No, you do not use "mono" for the first element
3. nitrogen tetrafluoride
No, you need to review prefixes
4. nitrogen trifluoride
Very good, click arrow to continue
5. none of the above
No, there is a correct answer
next problem
Prefixes

36. Practice Problem #10 No, you need to review prefixes
Krypton difluoride
Choose the correct formula for the compound
1. KrF4
No, you need to review prefixes
KrF2
Very good, click arrow to continue
3. KF2
No, "K" is not correct, see element list
4. K2F2
No, both an element & subscript are wrong
5. none of the above
No, there is a correct answer
next problem
Element List
Prefixes

37. Practice Problem #11 No, "mono" is used only for the last element
Choose the correct name for the compound
1. mononitrogen monoxide
No, "mono" is used only for the last element
2. nitrogen monoxygen
No, all binary compounds end in "ide"
3. mononitrogen oxide
No, "mono" is used only for the last element
4. nitride monoxide
No, only the last element ends in "ide"
5. none of the above
Very good, click arrow to continue
next problem
This is nitrogen monoxide

38. Practice Problem #12 No, there is not enough oxygen atoms
dioxygen difluoride
Choose the correct formula for the compound
1. OF2
No, there is not enough oxygen atoms OF
No, this says there are two molecules
3. O2F2
Very good, click arrow to continue
4. OF
No, there is not enough atoms
5. none of the above
No, there is a correct answer
next problem
Prefixes

39. Practice Problem #13 No, you need to review prefixes
BrF5
Choose the correct name for the compound
1. bromine hexafluoride
No, you need to review prefixes
2. boron pentafluoride
No, "B" is not correct, see element list
3. monobromine pentafluoride
No, "mono" is not used for the first element
4. bromine pentafluoride
Very good, click the arrow to continue
5. none of the above
No, there is a correct answer
next problem
Element List
Prefixes

40. dichlorine trifluoride
Practice Problem #14
dichlorine trifluoride
Choose the correct formula for the compound
1. Cl2F3
Very good, click arrow to continue
C2F3
No, "C" is not chlorine, see element list
ClF3
No, this says there are two molecules
4. Cl2F5
No, you need to review prefixes
5. none of the above
No, there is a correct answer
next problem
Element List
Prefixes

41. Practice Problem #15 No, iron is not correct, see element list
IF5
Choose the correct name for the compound
1. iron pentafluoride
No, iron is not correct, see element list
2. iron pentafluorine
No, an element & the ending are wrong
3. Iodine pentafluorine
No, all binary compounds end with "ide"
4. Iodine pentafluoride
Very good, click arrow to continue
5. none of the above
No, there is a correct answer
next problem
Element List

42. Practice Problem #16 No, "S" is not correct, see element list
silicon tetrabromide
Choose the correct formula for the compound
1. SBr4
No, "S" is not correct, see element list
ScBr4
No, "Sc" is not correct, see element list
3. SiB4
No, "B" is not correct, see element list
4. SiBr6
No, you need to review prefixes
5. none of the above
Very good, click the arrow to continue
next problem
The correct formula is SiBr4
Element List
Prefixes

43. Practice Problem #17 Very good, click arrow to continue
S4N4
Choose the correct name for the compound
1 tetrasulfur tetranitride
Very good, click arrow to continue
2. tetrasulfur nitride
No, the "nitride" needs a prefix
3. trisulfur trinitride
No, you need to review prefixes
4. tetrasulfur tetranitrogen
No, all binary compounds end in "ide"
5. none of the above
No, there is a correct answer
next problem
Prefixes

44. Practice Problem #18 No, "Ga" is not correct, see element list
Germanium dioxide
Choose the correct formula for the compound
1. GaO2
No, "Ga" is not correct, see element list
Ge2O2
No, there are too many subscripts
3. GeO2
Very good, click arrow to continue
4. Ge2O
No, both the subscripts are wrong
5. none of the above
No, there is a correct answer
next problem
Element List
Prefixes

45. Practice Problem #19 No, you do not use "mono" for the first element
BF3
Choose the correct name for the compound
1. monoboron trifluoride
No, you do not use "mono" for the first element
2. boron trifluorine
No, all binary compounds end with "ide"
3. boron trifluoride
Very good, click arrow to continue
4. bromine trifluoride
No, "Br" is not correct, see element list
5. none of the above
No, there is a correct answer
Element List

46. tetraphosphorus decasulfide
Practice Problem #20
tetraphosphorus decasulfide
Choose the correct formula for the compound
1. P6S9
No, you need to review prefixes
P4S9
No, you need to review prefixes
3. P4Si10
No, "Si" is not correct, see element list
4. Ph4S10
No, "Ph" is not correct, see element list
5. none of the above
Very good, click arrow to continue
next problem
The correct formula is P4S10
Element List
Prefixes

47. H H B Al Si Ge As Sb Te Po At

48. Element List return 1 Actinium Ac 2 Aluminum Al 4 Argon Ar
5 Arsenic As
6 Astatine At
7 Barium Ba
9 Beryllium Be
10 Bismuth Bi
12 Boron B
13 Bromine Br
14 Cadmium Cd
15 Calcium Ca
17 Carbon C
18 Cerium Ce
19 Cesium Cs
20 Chlorine Cl
21 Chromium Cr
22 Cobalt Co
23 Copper Cu
24 Fluorine F
Francium Fr
24 Gallium Ga
Germanium Ge
Gold Au
Helium He
Hygrogen H
Indium In
Iodine I
Iridium Ir
Iron Fe
Krypton Kr
Lanthanum La
Lead Pb
Lithium Li
Magnesium Mg
Manganese Mn
Mercury Hg
Molybddenum Mo
Neon Ne
Nickel Ni
Niobium Nb
Nitrogen N
Osmium Os
Oxygen O
Palladium Pd
Phosphorus P
Platinum Pt
Plutonium Pu
Polonium Po
Potassium K
Radium Ra
Radon Rn
return

49. Prefixes mono- 1 hepta- 7 di- 2 octa- 8 tri- 3 nona- 9
tetra- 4 deca
penta undeca- 11
hexa- 6 dodeca- 12
return