Section 9.1 Naming Ions

Chapter 9 Vocab        Acid Base Binary compound Law of definite proportions Law of multiple proportions Monatomic ion Polyatomic ion 2 Section 9.1: Naming Ions Read pages 252-259 Monatomic Ions 4   Ions that consist of a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons Two Types  Positive Ions ◼ Cations  Negative ◼ Anions Ions Cations 5    Positively charged ions Metal atom loses electrons Name stays the same Example: Name of Element: Aluminum Number of Valence Electrons: 3 Charge on Ion: +3 Name of Ion: Aluminum Naming Cations Practice 6 Element # of Valence Electrons Ion Formed Name of Cation Sodium Calcium 1 2 2 Na+ Ca2+ Mg2+ Sodium Calcium Magnesium Magnesium What is the rule for naming cations? DON’T CHANGE THE NAME. Anions 7    Negatively charged ions Nonmetal atom gains electrons Name changes to –ide ending Example: Name of Element: Iodine Number of Valence Electrons: 7 Charge on Ion: -1 Name of Ion: Iodide Naming Anions Practice 8 Element # of Valence Electrons Ion Formed Name of Anion Nitrogen 5 N3- Nitride Sulfur 6 S2- Sulfide Fluorine 7 F- Fluoride What is the rule for naming anions? CHANGE THE ENDING TO -IDE Note: 9 Groups 14 (4A) and 18 (8A) usually do not form ions 10 Ions of Transition Metals 11  Many of the transition metals form more than one cation with different ionic charges  Not  all transition metals have more than one charge Charges must be determined from the number of electrons lost These colorful solutions contain the transition metal ions Co3+, Cr3+, Fe3+, Ni2+, and Mn2+. Two Methods to Name Transition Metal Ions 12 1. 2. Stock System Classical Method Stock System 13   Preferred method of naming A Roman numeral in parentheses is placed after the name of the element to indicate the numerical value of the charge Number Roman Numeral 1 I 2 II 3 III 4 IV 5 V 6 VI Stock System Naming Practice 14 Ion Formed # Electrons Lost Stock Name Cu+ 1 Copper (I) ion Cu2+ 2 Copper (II) ion Pb2+ 2 Lead (II) ion Pb4+ 4 Lead (IV) ion Classical Method 15  In the past, scientists used the Latin names of elements. Example: Ferrum is Latin for Iron. Ferr- is the root of this word. Iron forms two ions: Fe2+ and Fe3+ Ion names: Fe2+ is the ferrous ion Fe3+ is the ferric ion 16 Practice Problems 17 a) Selenide (anion) b) Barium (cation) c) Phosphide (anion) Polyatomic Ions 18  What does the prefix poly mean?     MANY Polyatomic ions are composed of more than one atom Tightly bound groups of atoms that behave as a unit and carry a charge The names of most polyatomic ions end in –ite or –ate  Different Endings ◼ ◼ ◼ Ammonium → NH4+ Cyanide → CNHydroxide → OH- 19 Polyatomic Ions to memorize! 20 Formula NO3OHClO3SO42CO32PO43- Name Nitrate Hydroxide Chlorate Sulfate Carbonate Phosphate A closer look at a polyatomic ion 21 Superscript: shows the charge on the polyatomic ion Name: Phosphate 3PO4 What is the subscript on Phosphorus? 1 Subscript: shows the number of atoms of that element An important note: 22   Pay close attention to the names! Example:  Sulfide = S2- = SO42 Sulfite = SO32 Sulfate Quick Quiz Section 9.1 1. Which of the following are positively charged polyatomic ions? 24 (I) ammonium ion (II) perchlorate ion (III) iron (II) ion a. I only b. II only c. III only d. I and III 2. If the name of an ion ends in -ite or -ate, the ion is a 25 a. b. c. d. polyatomic cation. polyatomic anion. transition metal cation. monatomic anion.