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Period 6 Group 6. 4.2 – Naming and Writing Formulas for More Complex Numbers. Introduction to Nomenclature (II). Common Polyatomic Ions Naming Compounds with Polyatomic Ions Naming Acids Based on its Anions Common Acids Writing Formulas/Names with Given Information. Common Polyatomic Ions.
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Period 6 Group 6 4.2 – Naming and Writing Formulas for More Complex Numbers
Introduction to Nomenclature (II) Common Polyatomic Ions Naming Compounds with Polyatomic Ions Naming Acids Based on its Anions Common Acids Writing Formulas/Names with Given Information
Common Polyatomic Ions • 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.
Common Polyatomic Ions • 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.
Naming Compounds with Polyatomic Ions • 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.
Naming Acids Based on its Anions 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. 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.
Common Acids Acid: A substance that produces hydrogen ions (H+) in solution; a proton donor.
Common Acids 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-
Common Acids 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.
Writing Formulas/Names with Given Information • 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.
Writing Formulas/Names with Given Information • Example/Question 5- Write the formula for iodine dihydrogen phosphate. • Given info: name • Iodine = I- • Dihydrogen phosphate = H2PO4- • I- + H2PO4- • = IH2PO4
Quiz! (: • 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?
Quiz Answers 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.
References • 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 • Microsoft PowerPoint Clip Art