Naming Binary Ionic Compounds

1. Naming Binary Ionic Compounds

2. What is a binary ionic compound? • IONIC COMPOUND • Formed from ionic bonds • Metal and nonmetal • Left of stepline on PT=metal • Right of steplineon PT=nonmetal • BINARY • Prefix “bi” means 2 • A binary compound contains teo different kinds of elements

3. A Common Example • NaCl • Na=sodium=metal=cation • Cl=chlorine=nonmetal=anion • Two elements joined by an ionic bond • Na loses electron to form positive ion • Cl gains electron to form negative ion • Ions are attracted by electrostatic charges

4. How do we name it? Name the metal Na Sodium Name the non-metal with an “-ide” ending Cl Chlorine Chlorine Chloride

5. NaCl sodium chloride

6. Is it always this easy? • Almost…but not quite! • Group 1,2, and 13 metals have charges determined by their position on the periodic table…1+, 2+. 3+ • Ag is always 1+ • Cd is always 2+ • Zn is always 2+

7. Transition metals • The charges of transition metal cations (and a few others under the stepline) vary • The charge of these cations must be calculated to balance the negative charge of the anions involved

8. CuS is copper (II) sulfide • Copper can have different charges • What is it paired up with and what ratio is needed to have a net charge of zero? • The anion is sulfide • Sulfur produces a sulfide ion which is 2-. (You know this from the periodic table.) • The cation is copper • One Cu is present, so its charge must be 2+ to balance the 2- charge from the S • Name cation, show charge as Roman numeral in parentheses, name anion with -ide ending.

9. Fe2S3 is iron (III) sulfide • Sulfide is 2- (from its position on periodic table) • There are 3 sulfide 3 x 2- = 6- • Iron can have different charges • 2 iron ions balance a 6- charge • 2 x ? = 6+ • Iron’s charge in this compound is 3+ • Name cation, show charge as Roman numeral in parentheses, name anion with -ide ending. • Reverse criss-cross!