1. Chapter 7 Part 1: Chemical Formulae and Naming Ionic Compounds

2. Formulae What does CCl 4 really mean? What does CCl 4 really mean? –Is this ionic or covalent? Find the electronegativity of each element and use the table on page 162 to find out! Find the electronegativity of each element and use the table on page 162 to find out! –How many atoms of each element are involved? Symbols Symbols What does the subscript mean? What does the subscript mean? –What is it named? Naming depends on whether the compound is ionic or covalent. Naming depends on whether the compound is ionic or covalent.

3. Formulae How about Al 2 (SO 4 ) 3 ? How about Al 2 (SO 4 ) 3 ? –What do the parentheses mean? Parentheses surround polyatomic ions Parentheses surround polyatomic ions The subscript on the parentheses means EVERYTHING inside is multiplied The subscript on the parentheses means EVERYTHING inside is multiplied –Does the compound have covalent or ionic bonds? –How many atoms are in this compound?

4. Naming Ionic Compounds Monatomic Ions Monatomic Ions –Ions formed from single atoms –Charge determined by whether the atom gains or loses electrons (and how many) –Example: Ca –Example: F

5. Naming Ionic Compounds Naming monatomic ions Naming monatomic ions –Ending of element’s name (usually –ine or –ium) dropped –Suffix –ide added –Example: Na + –Example: S -2

6. Naming Ionic Compounds Binary Ionic Compounds Binary Ionic Compounds –Composed of 2 different elements’ ions Chemical formula Chemical formula –Sum of charges of ions must equal zero! –Crossing over may be used to determine subscripts –Example: Al bonded to S –Example: Mg bonded to I

7. Naming Ionic Compounds Binary Ionic Compounds: Nomenclature Binary Ionic Compounds: Nomenclature Name of cation given first (no suffix) Name of cation given first (no suffix) Name of anion given with suffix Name of anion given with suffix Usually number of ions not given, since we know the charges Usually number of ions not given, since we know the charges Example: Al 2 S 3 Example: Al 2 S 3 Example: MgI 2 Example: MgI 2

8. Naming Ionic Compounds Sample Problem 7-1 Sample Problem 7-1 Write formula and give name: Write formula and give name: –Bonding of zinc and iodine –Bonding of zinc and sulfur

9. Naming Ionic Compounds Stock System Stock System Used for ions (usually cations) with more than one possible charge Used for ions (usually cations) with more than one possible charge –Is NOT used for ions that can have only one charge Roman numeral used to indicate charge Roman numeral used to indicate charge Roman numeral is in parentheses directly after ion’s name Roman numeral is in parentheses directly after ion’s name Example: Fe +2 = Example: Fe +2 = –Iron (II) Example: Fe +3 = Example: Fe +3 = –Iron (III)

10. Naming Ionic Compounds Sample Problem 7-2 Sample Problem 7-2 Write the formula and give the name for the compound formed by Cr +3 and F -. Write the formula and give the name for the compound formed by Cr +3 and F -. Write the symbols with charges: Write the symbols with charges: –Cr +3 F -1 –Determine subscripts by using charges –Formula is Cr +3 F 3 -1 –Name: Chromium (III) fluoride

11. Naming Ionic Compounds Polyatomic ions! Polyatomic ions! You MUST know the polyatomic ions! You MUST know the polyatomic ions! Page 210: Page 210: –Ammonium –Acetate –Chlorate –Bicarbonate –Hydrogen sulfate

12. Naming Ionic Compounds Polyatomic ions! Polyatomic ions! You MUST know the polyatomic ions! You MUST know the polyatomic ions! –Hydroxide –Nitrate –Nitrite –Permanganate –Carbonate

13. Naming Ionic Compounds Polyatomic ions! Polyatomic ions! You MUST know the polyatomic ions! You MUST know the polyatomic ions! –Chromate –Sulfate –Sulfite –Phosphate

14. Naming Ionic Compounds Name of most common polyatomic ion ends in –ate Name of most common polyatomic ion ends in –ate –Example: ClO 3 -1 is chlorate ion Ion with one less oxygen ends in –ite Ion with one less oxygen ends in –ite –Example: ClO 2 -1 is chlorite ion Ion with less oxygen than –ite ion is called hypo – ion name –ite Ion with less oxygen than –ite ion is called hypo – ion name –ite –Example: ClO -1 is hypochlorite ion Ion with more oxygen than –ate ion is called per – ion name –ate Ion with more oxygen than –ate ion is called per – ion name –ate –Example: ClO 4 -1 is perchlorate ion

15. Naming Ionic Compounds Sample problem 7-3 Sample problem 7-3 Write the formula for tin (IV) sulfate Write the formula for tin (IV) sulfate First write the symbols First write the symbols –Sn +4 SO 4 -2 Check the charges: sum must be zero Check the charges: sum must be zero If you need more than one polyatomic ion, use parentheses If you need more than one polyatomic ion, use parentheses –Sn +4 ( SO 4 -2 ) 2 Answer must use simplest whole number ratio!

16. Ionic Compounds Write the formula for: Write the formula for: Copper (II) nitrate Copper (II) nitrate Potassium iodide Potassium iodide Potassium permanganate Potassium permanganate Iron (III) nitrate Iron (III) nitrate

17. Ionic Compounds Name these compounds: Name these compounds: Ag 2 S Ag 2 S NaMnO 4 NaMnO 4 Fe(ClO) 2 Fe(ClO) 2 NH 4 NO 3 NH 4 NO 3