In molecular bonding, molecules form, and they only include these atoms:

1. Taking a break from IONIC compounds, which let metals and non-metals bond by transferring electrons, then being wildly attracted together, Today we will start our examination of MOLECULAR COMPOUNDS, which only contain the NONMETALS, and bond by the sharing of electrons. These bonds are not quite as strong, but strong enough that you can’t pry them apart (I can).

2. In molecular bonding, molecules form, and they only include these atoms: Hydrogen, boron, carbon, nitrogen, oxygen, fluorine, silicon, phosphorous, sulfur, chlorine, arsenic, selenium, bromine, and iodine. Tellurium is also included, but you won’t see it in our class. The Noble gases are nonmetals, but they don’t make any bonds ever.

3. You know many molecular compounds already, such as Water H2O Carbon dioxide CO2 and Carbon monoxide CO From these three atoms we will create the 2 rules to naming these kinds of compounds, the FIRST NAME RULE, and the SECOND NAME RULE

4. Naming Rules for Molecular Compounds First name Rule: when the first part is a single atom, just say the name of the atom when the first part is a multiple, you have to use a prefix Second name Rule: always use a prefix to name these, end with –ide (same as the ionic compounds, oxygen is oxide, sulfur is sulfide, etc.) Water H2O (multiple first part, so DIHYDROGEN MONOXIDE) Carbon dioxide CO2 (single first part, so CARBON DIOXIDE) Carbon monoxide CO (single first part, so CARBON MONOXIDE)

5. PREFIXES for first ten numbers: MONO DI TRI TETRA PENTA HEXA HEPTA OCTA NONA DECA

6. Let’s Name Some Compounds SO3 SO2 BCl3 PCl5 N2O5 OF2 B2O3

7. Let’s Name Some Compounds SO3 sulfur trioxide SO2 sulfur dioxide BCl3 boron trichloride PCl5 phosphorous pentachloride N2O5dinitrogenpentoxide OF2 oxygen difluoride B2O3 diborontrixoide

8. The WHITE periodic tables will show us how to make different compounds. Look at the Hydrogen box and the oxygen box. NOTICE THE SELECTED OXIDATION STATES in the table key. These are NOT ION CHARGES, but they do look like them. H O +1 -2 -1

9. H O +1 -2 -1 We need to match up the positive and negative numbers and see how we can sum them to ZERO. Those show the real compounds that can form. These ARE NOT ION CHARGES (although oxygen does make a -2 ion). These are selected oxidation states, or a number pattern to show us how to make compounds, and how to know which ones are NOT REAL. When you have pairs of negative numbers, or pairs of positive numbers, they can never sum to zero, so they are not used. Above, the negative 1 and negative 2 are not used, they don’t “work” mathematically.

10. H O +1 -2 -1 The negative 1 is out on this problem. The +1 and the -2 can sum to zero when you have two hydrogens combining to one oxygen… (+1) + (+1) + (-2) = ZERO Hydrogen and oxygen combine only in a 2:1 ratio, as H2O. No other H-O Compounds exist.

11. Let’s See all of the Carbon-Oxygen Compounds now. C O

12. Let’s See all of the Carbon-Oxygen Compounds now. Negative and Negative are out. C O -4 +2 -2 +4 1:1 ratio makes CO or carbon monoxide 1:2 ratio makes CO2 or carbon dioxide These are the ONLY 2 Carbon-Oxygen compounds that are real.

13. 13

14. Can carbon trioxide CO3exist? How about dicarbon monoxide C2O?

15. Last one today, what are the formulas and names of all the SILICON and FLUORINE compounds? Si F

16. Last one today, what are the formulas and names of all the SILICON and FLUORINE compounds? (-4 and -1 do not work here) Si F -4 -1 +2 +4 1:2 ratio works, Silicon Difluoride SiF2 1:4 ratio is also good Silicon tetrafluoride SiF4