1. CHEM 105 Naming Inorganic Compounds Containing Polyatomic Ions

2. 2

3. A polyatomic ion is an ion that contains two or more elements.

4. They usually consist of one or more cations combined with a negative polyatomic ion. Compounds containing polyatomic ions are composed of three or more elements.

5. When naming a compound containing a polyatomic ion, name the cation first and then name the anion.

6. The ions are what is actually present. This is the way the formula is written.

7. The ions are what is actually present.

8. Prefixes and Suffixes Elements that Form More than One Polyatomic Ion with Oxygen

9. Anions ending in -ate always contain more oxygen than ions ending in -ite. nitratenitrite

10. Anions ending in -ate always contain more oxygen than ions ending in -ite. phosphatephosphite

11. Anions ending in -ate always contain more oxygen than ions ending in -ite. sulfatesulfite -ate and –ite do not indicate the number of oxygen atoms.

12. perper- denotes anions with more oxygen than the -ate form. perchloratechlorate

13. -per is a short form of hyper, meaning more.

14. hypohypo- denotes anions with less oxygen than the -ite form. chloratehypochlorite -hypo means less.

16. Four ions do not use the –ate/ite system. hydroxide hydrogen sulfide cyanide peroxide

17. There are three common positively charged polyatomic ions. ammoniumhydronium mercury(I)

19. AcidsAcids

20. The other element is usually a nonmetal, but it can be a metal. Its first element is hydrogen. Its remaining elements include oxygen and form a polyatomic ion. Oxy-acids contain hydrogen, oxygen and one other element.

21. Hydrogen in an oxy-acid is not expressed in the acid name. The word acid in the name indicates the presence of hydrogen.

22. contains oxygen contains sulfur contains hydrogen indicates hydrogen sulfuric acid

23. Anions ending in -ate always contain more oxygen than ions ending in -ite. phosphatephosphite

24. Naming the Acid Based on the Name of the Polyatomic Ion Ending of Polyatomic Ion more oxygen less oxygen ite ate Ending of Acid ous ic

25. Examples

26. sulfite sulfurous acid

27. sulfate sulfuric acid

28. nitrite nitrous acid

29. nitrate nitric acid

32. Writing Formulas From Names of Compounds

33. A chemical compound must have a net charge of zero.

34. If the compound contains ions, then the charges on all of the ions must add to zero.ryan likes boys

35. Write the formula of calcium chloride. Step 1. Write down the formulas of the ions. Ca 2+ Cl - Step 2. Combine the smallest numbers of Ca 2+ and Cl - so that the sum of the charges equals zero. (2+) + 2(1-) = 0 The correct formula is CaCl 2 The lowest common multiple of +2 and –1 is 2 The cation is written first. The anion is written second. (Ca 2+ ) + 2(Cl - ) = 0

36. Write the formula of barium phosphide. Step 1. Write down the formulas of the ions. Ba 2+ P 3- Step 2. Combine the smallest numbers of Ba 2+ and P 3- so that the sum of the charges equals zero. 3(2+) + 2(3-) = 0 The correct formula is Ba 3 P 2 The lowest common multiple of +2 and –3 is 6 3(Ba 2+ ) + 2(P 3- ) = 0 The cation is written first. The anion is written second.

37. Write the formula of magnesium oxide. Step 1. Write down the formulas of the ions. Mg 2+ O 2- Step 2. Combine the smallest numbers of Mg 2+ and O 2- so that the sum of the charges equals zero. (2+) + (2-) = 0 The correct formula is MgO The lowest common multiple of +2 and –2 is 1 ( Mg 2+ ) + (O 2- ) = 0