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Homework: Chemical Formulas II

Answer the following questions using complete sentences.

Part I

  1. What happens at the molecular level when an electrolyte solution is conducting electricity?
  2. Why don’t non-electrolyte solutions conduct electricity?
  3. When you look at the formula of a compound how can you tell whether it is a molecular compound or an ionic compound?
  4. Which elements in the periodic table have only one possible charge in ionic compounds when they appear as monatomic ions? Use group numbers to identify and write down the charges expected for these ions. For example, Group 1 has elements that all form an ion with a +1 charge.
  5. Why is the formula of a compound made of magnesium ions (Mg2+) and oxide ions (O2–) written as MgO and not Mg2O2?
  6. Explain why you can’t change the subscripts in the formulas of polyatomic ions like PO43- or NH4+.
  7. When are parentheses necessary in writing the formulas of ionic compounds? Why are they used?
  8. What is the meaning of the roman numerals after the names of some metal elements’ ions? For example, Fe2+ is called iron(II).
  9. When writing the name of an ionic compound containing a metal ion which sometimes has one ionic charge and sometimes has another how do you know which ion name to use? For example, PbCO3 and Pb(CO3)2 are different compounds with different names. What are their names and how did you figure it out?
  10. Some molecular compounds have different names depending on whether they are pure or dissolved in water. Give the names of the pure compounds HF, HCl, HBr, HI, H2S. Also, give their names when dissolved in water.
  11. What are oxyanions? Write the name and formula of all four oxyanions of chlorine.
  12. What are oxyacids? Give the name and formula of the oxyacids of chlorine and the oxyacids based on phosphate, sulfate, and nitrate.
  13. What do the suffixes –ide, –ite, and –ate mean?
  14. Using resources such as a recent lab, books, or the internet identify three ionic compounds, three polar compounds, and three non-polar compounds.
  15. What does the solubility rule that “Like dissolves like” mean?
  16. What are the Lewis dot diagrams for the following elements?
    Li       S       I       Kr       Mg       Ba       Cs       As

Part II

Name the following compounds. The compounds may be ionic, molecular, acids, or elements. Decide which category the formula belongs to and name it appropriately.

  1. CrO3
  2. PCl3
  3. NO
  4. Cr2O3
  5. Ag2S
  6. N2O4
  7. MnO2
  8. N2F4

  1. HClO3
  2. BaSO3
  3. H2SO4
  4. Cl2
  5. PbCl2
  6. Sn(NO2)2
  7. CuNO3
  8. Ti3(PO4)4

Part III

Write formulas for the following compounds.

  1. Hypobromous Acid
  2. Carbon Dioxide
  3. Ammonium Sulfate
  4. Barium Nitrate
  5. Calcium Phosphate
  6. Tin(IV) Iodide
  1. Hydrochloric Acid
  2. Nickel(III) Carbonate
  3. Zinc Bromide
  4. Ammonia
  5. Chromium(II) nitrate
  6. Potassium Cyanide
This homework belongs with the Chemical Formulas and Compounds group activity.
Additional Naming Practice Problems
Homework I
Homework III
Many problems were inspired by those at Mr. Basset’s Site.
ChemTeam Additional Naming Information and Practice
(has lots of exercises with answers)

Last updated: Feb 26, 2014        Home