Period 6Group 6

I. Common Polyatomic Ions

II. Naming Compounds with

Polyatomic Ions

III. Naming Acids Based on its Anions

IV. Common Acids

V. Writing Formulas/Names with

Given Information

Polyatomic ion: An ion consisting of two or more atoms bound together (a binary compound only consists of two elements)•Example/Question 1: What is special about the polyatomic ions such as hydroxide, peroxide, and cyanide compared to the other common polyatomic ions?

•Answer: They are the only ones with an –ide ending.

Oxyanion: A polyatomic ion containing at least one oxygen atom & one or more atoms of at least one other element.

Common polyatomic ions must be memorized. Use the suffix –ite (smaller # of oxygen atoms)

or –ate (larger # of oxygen atoms) when there are two members in an oxyanion series.

Use the prefixes hypo- (less than) and per- (more than) when more than two oxyanions make up a series.

To name compounds with polyatomic ions, polyatomic ions must be recognized by its composition and charge.

When a metal is present that forms more than one cation, a Roman numeral is required.

Parentheses are used to enclose the ion and a subscript is written after the closing parenthesis.

Example/Question 2: What must we add to specify the cation charge of the metal in ionic compounds containing polyatomic ions?◦ Answer: We must add a Roman numeral.

Example/Question 3: If the anion name ends in –ite, what is the suffix used in the acid name?

Answer: The suffix used in the acid name would be –ic.

Example/Question 4: What are the rules to naming acids based on its anion composition?

Answer: The rules to naming acids if the anion doesn’t contain oxygen, is the acid is named with the prefix hydro- and the suffix –ic. When the anion contains oxygen, the acid name is formed from the root name of the central element of the anion or the anion name with a suffix of –ic or –ous. Use –ic when the anion name ends in –ate or use –ite when the anion name ends in –ite.

*Refer to the orange box on the left for more information.

Acid: A substance that produces hydrogen ions (H+) in solution; a proton donor.

Acids That Do Not Contain Oxygen

HF – hydrofluoric acid HCl – hydrochloric acid HBr – hydrobromic acid HI – hydroiodic acid HCN – hydrocyanic acid H2S – hydrosulfuric acid

Note: All of the names of acids that don’t have oxygen have the prefix hydro-

Acids That Do Contain Oxygen

HNO3 – nitric acid HNO2 – nitrous acid H2SO4 – sulfuric acid H2SO3 – sulfurous acid H3PO4 – phosphorus acid HC2H3O2 – acetic acid

*Common acids must be memorized.

Learn the following: (for each of the common polyatomic ions)◦ name◦ composition◦ charge

These all must be learned in order to write the formula for a given name or to write the name for a given formula.

Example/Question 5- Write the formula for iodine dihydrogen phosphate.

Given info: name Iodine = I- Dihydrogen phosphate = H2PO4-

◦I- + H2PO4-

= IH2PO4

1. What is the difference between a binary compound

and an ionic compound containing polyatomic ions?

2. What do we add when more than one polyatomic

ion appears in a chemical formula?

3. What is the prefix & suffix attached to the root

name for the element, if the anion doesn’t contain

oxygen?

4. What do the acids names that do not contain

oxygen all have in common?

5. What is the name for Ti(NO3)3?

1. An ionic compound containing polyatomic ions contains more than 2 elements.

2. We add parentheses to enclose the ion and a subscript after the closing parenthesis.

3. The prefix is hydro- and the suffix is –ic. 4. They all have the prefix hydro-. 5. The name is titanium nitrate.

http://professorchemistry.com/store/image/2uco9/CD_ROMS_WRITING_CHEMICAL_FORMULAS_POLYATOMIC_IONS.jpg

http://www.iun.edu/~cpanhd/C101webnotes/chemical-nomenclature/images/polyions.jpg

http://www.chemcool.com/referencetables/tableE5.jpg

http://www.ucc.edu/NR/rdonlyres/141FB85E-841F-452C-9C24-1FA43CF9A342/0/ChemistryNamingCompounds3.pdf

http://www.classzone.com/cz/books/woc_07/secured/resources/applications/ebook/index.jsp

http://hyperphysics.phy-astr.gsu.edu/Hbase/Chemical/imgche/comacid.gif

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