Name:_______________________ Date: _______________________
Naming Binary Ionic Compounds
● Binary Ionic compounds are between a metal (positively charged cation) and a nonmetal
(negatively charged anion)
Naming from Formulae Rules
1. The first element in the formula is the one with the positive ionic charge; it retains its own
name, e.g., in CaCl2,
➢ the first element Ca is called calcium
2. The second element is chlorine with a negative ionic charge; its name is modified to end
in “-ide”, e.g., CaCl2,
➢ the second element Cl (chlorine) is called chloride
Write the name for each compound:
1. AlF3 ____________________________ 8. MgCl2 ____________________________
2. Li3P ____________________________ 9. BeO ____________________________
3. MgS ____________________________ 10. BeI2 ____________________________
4. HBr ____________________________ 11. NaI ____________________________
5. CaH2 ____________________________ 12. CaBr2 ____________________________
6. K2O ____________________________ 13. K3N ____________________________
7. Na2S ____________________________ 14. Al2S3 ____________________________
Writing Formulae from Names
1. Write the symbols of the two elements in the order in which they appear in the name. Thus
for aluminum oxide, AlO.
2. Mentally mark in the charges/valences. Therefore AlO becomes Al+3O-2. Use the cross-over
rule with the valence numbers (omit signs). Al+3O-2 gives Al2O3.
3. Divide subscripts by the highest common factor, if necessary. Mg+2O-2 becomes Mg2O2,
which cancels to MgO. Note: canceling subscripts is only permitted for ionic compounds.
Example 1. aluminum oxide Example 2. magnesium oxide
Write the formulae for the following compounds:
1. calcium iodide __________ 9. magnesium oxide __________
2. potassium bromide __________ 10. hydrogen sulfide __________
3. sodium fluoride __________ 11. lithium sulfide _________
4. beryllium bromide __________ 12. calcium phosphide __________
5. calcium oxide __________ 13. aluminum bromide __________
6. magnesium nitride __________ 14. sodium nitride __________
7. aluminum nitride __________ 15. magnesium hydride __________
8. potassium iodide __________ 16. potassium oxide __________
Naming Binary Ionic Compounds
● Binary Ionic compounds are between a metal (positively charged cation) and a nonmetal
(negatively charged anion)
Naming from Formulae Rules
1. The first element in the formula is the one with the positive ionic charge; it retains its own
name, e.g., in CaCl2,
➢ the first element Ca is called calcium
2. The second element is chlorine with a negative ionic charge; its name is modified to end
in “-ide”, e.g., CaCl2,
➢ the second element Cl (chlorine) is called chloride
Write the name for each compound:
1. AlF3 ____________________________ 8. MgCl2 ____________________________
2. Li3P ____________________________ 9. BeO ____________________________
3. MgS ____________________________ 10. BeI2 ____________________________
4. HBr ____________________________ 11. NaI ____________________________
5. CaH2 ____________________________ 12. CaBr2 ____________________________
6. K2O ____________________________ 13. K3N ____________________________
7. Na2S ____________________________ 14. Al2S3 ____________________________
Writing Formulae from Names
1. Write the symbols of the two elements in the order in which they appear in the name. Thus
for aluminum oxide, AlO.
2. Mentally mark in the charges/valences. Therefore AlO becomes Al+3O-2. Use the cross-over
rule with the valence numbers (omit signs). Al+3O-2 gives Al2O3.
3. Divide subscripts by the highest common factor, if necessary. Mg+2O-2 becomes Mg2O2,
which cancels to MgO. Note: canceling subscripts is only permitted for ionic compounds.
Example 1. aluminum oxide Example 2. magnesium oxide
Write the formulae for the following compounds:
1. calcium iodide __________ 9. magnesium oxide __________
2. potassium bromide __________ 10. hydrogen sulfide __________
3. sodium fluoride __________ 11. lithium sulfide _________
4. beryllium bromide __________ 12. calcium phosphide __________
5. calcium oxide __________ 13. aluminum bromide __________
6. magnesium nitride __________ 14. sodium nitride __________
7. aluminum nitride __________ 15. magnesium hydride __________
8. potassium iodide __________ 16. potassium oxide __________
