1. 9-1 NAMING IONS MAIN IDEAS 1.MONOATOMIC ION 2.POLYATOMIC ION Objective Identify charges of monoatomic ions. Define polyatomic ions & write the names & formulas. Identify the 2 common endings for the the names of most polyatomic ions. IaN PG. 3 Key Concepts: x3 (See page 253) Robert Orben

2. C HAPTER 9 Chemical Names and Formulas

3. R EVIEW : I ONIC COMPOUNDS Ionic compounds formed from monoatomic ions… Nonmetals combining with metals Attraction is from opposite charges (cations & anions) Cations come from groups 1, 2 & 3 Anions come from groups 5, 6, & 7 Net charge of the compound is always zero (neutral) To name the cations… Just use the name of the metal and the word “ion” or “cation” Examples: Na + = sodium ion or sodium cation K + = potassium ion or potassium cation Mg 2+ = magnesium ion or magnesium cation

4. To determine the charge of a nonmetal, we looked at the valence electrons (which was the same as the group number) and then decided how many electrons the atom wanted to gain to be like a noble gas. Ex. Oxygen in group 6, has 6 valence electrons – so it wants to gain 2 more electrons to have a full octet. That gives it a net charge of 2- Another method is to just subtract the group number from 8 to decide on the net charge. Ex. 5A6A7A NOF PSCl SeBr 3-2-1-

5. N AMING ANIONS Add the suffix –ide to the element name. Ex. Fluoride Bromide Chloride Iodide Nitride Selenide Sulfide

6. I ONS OF TRANSITION METALS Transition metals are in groups 1-8B (It’s the B’s!) Many of the transition metals form more than 1 cation with different ionic charges. Ex. Fe 2+ and Fe 3+ Ex. Pb 2+ and Pb 3+

7. N AMING IONS OF TRANSITION METALS Two different naming systems are used: 1. The Stock System (preferred) A Roman numeral is placed in parentheses after the name of the element to indicate the value of the charge. Ex. Fe 2+ = iron(II) ion Fe 3+ = iron(III) ion 2. The Classical System This system uses different suffixes to differentiate… -ous is tacked on to the smaller charge -ic is tacked on to the larger charge Ex. Fe 2+ = ferrous ion Fe 3+ = ferric ion **Note that the original root name of the element is being used (ferrum = iron)

8. B ACK TO THE ROOTS … An ExampleRoot Name of Element Element as we Know it Stannous ionStannum (Latin) Tin Ferrous ionFerrum (Latin) Iron Plumbous ionPlumbum (Latin) Lead Cuprous ionCyprium (Latin) Copper

9. M ISC … A disadvantage of the classical naming system is that you cannot tell the actual charge of the ion by the name. (this is what makes the stock system better) Some transition metals only form 1 type of ion and do not use a Roman numeral.