1. MOLECULAR COMPOUNDS INB PAGE 9

2. ESSENTIAL QUESTIONS How is naming molecular compounds different from naming ionic compounds?

3. PAGE 8 OF INB 1Mono 2 Di 3 Tri 4 Tetra 5 Penta 6 Hexa 7 hepta 8 Octa 9 Nona 10 Deca

4. MOLECULAR COMPOUNDS 2 Methods: Oxidation numbers and Prefixes Rules for prefixes: 1 st element: lowest group # goes first. If same group, largest period goes first. If only one atom it does not get a prefix. More then one atom use corresponding prefix

5. MOLECULAR COMPOUNDS 2 nd Element: use corresponding prefix always and change ending to –ide. General rules: O or A at the end of the prefix is dropped if the element starts with a vowel. Ex. Mono-oxide => monoxide.

6. EXAMPLES: P 4 O 10 => Tetraphosphorus Decoxide CO 2 => Carbon Dioxide

7. PRACTICE PROBLEMS S 2 F 10 SF 6 N 2 O 3 S 2 Cl 2 P 2 O 3 CBr 4 P 4 O 6

8. OXIDATION NUMBERS Page 11 of INB

9. OXIDATION NUMBERS The general distribution of electrons among bonded atoms. Don’t have an exact physical meaning Can be very arbitrary Useful in naming compounds, writing formulas, and balancing equations.

10. OXIDATION NUMBERS Rules: Shared electrons are assumed to belong to the more electronegative element. For pure elements oxidation number = 0 Fluorine is always -1 O is -2, unless combine with F, then 2+

11. OXIDATION NUMBERS More electronegative element is assigned oxidation number = what its anion would be. Less electronegative element gets oxidation number = what it would be as a cation.

12. OXIDATION NUMBERS Hydrogen is +1, unless with a metal then it is -1 Sum of all the oxidation numbers in a compound must equal zero Sum of all oxidation numbers equals the charge for ions.

13. SOLVING PROBLEMS: 1) Place known oxidation numbers, and multiply by the number of atoms. 2) Use the rule that the sum of all oxidation numbers must equal zero to place remaining oxidation numbers. 3) use stock system (like the roman numerals) to name the elements.

14. PRACTICE PROBLEMS HCl CF 4 SO 2 HNO 3 P 4 O 10 N 2 O 5 CLO 3 -