Naming Ionic Molecular

(Covalent) Compounds

Directions for Naming Simple Ionic and Molecular Compounds

Ionic and molecular compounds are named differently. Here are three steps to follow to name each type.

Step #1: Determine whether the compound is ionic or molecular.

-How will you know if a compound is ionic or molecular?

-Ioniccompounds are made of ionic bonds between metals and nonmetals.

-Molecularcompounds are made of covalent bonds between nonmetal and nonmetals.

Step #2: If Ionic, write the metal name first then the “root” of the non-metal followed by the suffix, “-ide.”

-Examples: KCl is potassium chloride, MgCl2 is magnesium chloride, & Al2S3 is aluminum sulfide

Notice you do not include how many of each element are in the compound. There was no mention of the 2 or the 3 in the formula for aluminum sulfide. This is because there is only one combination for aluminum and sulfur and it is always 2 aluminums and 3 sulfurs. How the 2 and 3 and other numbers are found will be revealed later when you learn formula writing.

Step #3: If Molecular, write the name of the first atom in the formula with a prefix indicating how many of the

atom there are. Then, follow with the second atom including its prefix and finally the second atom also ends in “ide” just like ionic compounds. The prefixes to use are located in Table 3 on p. 228 of your textbook.

-Examples: N2O4dinitrogen tetraoxide, PCl5 phosphorus pentachloride, CO carbon monoxide

(mono is not used for the 1stelement in the compound; only the 2nd)

Prefixes are used because the numbers are not set like they are in ionic compounds. For example, nitrogen and oxygen can bond in many combinations, NO, NO2, N2O, N2O5 etc… Because of this diversity, chemists use the “prefixes” that are added to element names to indicate how many of each element are in the compound.

Summarizing the Steps

1. Summarize the above steps in your own words on a separate sheet of paper (staple to the back of this

paper). Feel free to summarize using words, flowcharts, numbered steps, etc. This is not a reference sheet.

Ionic vs. Molecular

Place an I or an M in the blank next to the following compounds to indicate ionic (I) vs molecular (M).

2. KBr_____ 3. CaCl2 ____ 4. Fe2S3 ____ 5. N2H4 _____ 6. Mg3N2 _____ 7. CBr4 ____

8. CO2 _____ 9. CO _____10. NaCl _____ 11. NH3 _____ 12. CuSO4 _____ 13. NO ____

Ionic Compounds

Write the name of each ioniccompound, changing the ending to –ide. Do not use prefixes

14. LiO______

15. CaCl2______

16. CrBr3______

17. Zr2S______

18. BaI2______

19. CsO______

20. ZnSe______

21. Ag3N______

22. Cd3P2______

Prefixes for Molecular Compounds

23.Write down the numerical prefixes for subscript numbers 1 – 10.

Molecular Compounds

Write the name of each molecular compound, changing the ending to –ide. Useprefixes.

24. CO2______

25. CO______

26. NH3______

27. ClO2______

28. P4S3______

29. CI4______

30. H2O______

31. XeF4______

32. N2O5______

Mixed Review

Name the following after determining if the compound is ionic or molecular.

33. Mn2O3______

34. Cs2O______

35. P4O10______

36. LiBr______

37. AsCl3______

38. NBr3______