1. BINARY MOLECULAR COMPOUNDS
molecule: electrically neutral group of atoms that acts as a unit
composed of nonmetals
electrons are shared (covalent): NO CHARGES
no criss-cross, no reducing subscripts
can combine in more than one way

2. NAMING BINARY MOLECULES
prefixes used to denote multiple atoms of one element in a molecule 1
mono- 6
hexa- 2
di- 7
hepta- 3
tri- 8
octa- 4
tetra- 9
nona- 5
penta- 10
deca-

3. NAMING BINARY MOLECULES
2nd element in name ends in –ide
for oxides: if the prefix ends in
a or o, LEAVE OUT the a or o
monooxide becomes monoxide
tetraoxide becomes tetroxide,
etc.

4. NAMING BINARY MOLECULES
if there is ONE atom of the first element, omit the prefix mono–
ex: CO
carbon monoxide
NOT monocarbon monooxide

5. WRITING NAMES CO carbon monoxide CO2 carbon dioxide N2O
dinitrogen monoxide
Cl2O8
dichlorine octoxide

6. WRITING NAMES OF2 oxygen difluoride N2O5 dinitrogen pentoxide P4O10
tetraphosphorus decoxide
SO3
sulfur trioxide

7. WRITING FORMULAS nitrogen trifluoride NF3 disulfur dichloride S2Cl2
dinitrogen tetroxide
N2O4
carbon tetrachloride
CCl4

8. DIATOMIC MOLECULES molecules with 2 atoms of the same element
there are 7 – know them!
N2 O2 H2 Cl2 I2 F2 Br2 or
Br2 I2 N2 Cl2 H2 O2 F2

9. LEWIS DOT DIAGRAMS (ELECTRON DOT DIAGRAMS)
show the valence electrons as dots
inner electrons and atomic nuclei are represented by the symbol

10. LEWIS DOT DIAGRAMS (ELECTRON DOT DIAGRAMS)
group 1A: 1 valence e-
group 2A: 2 valence e-, etc.

11. LEWIS DOT DIAGRAMS (ELECTRON DOT DIAGRAMS)
diatomic molecules

12. LEWIS STRUCTURES: STEPS
1. Count valence electrons and bonds using periodic table and octet rule – make a chart to get valence and shared electrons
2. Choose an arrangement of atoms (carbon in center, hydrogen or halogens on outside)

13. LEWIS STRUCTURES: STEPS
3. Put in calculated number of bonds; single bonds first, then multiple bonds if necessary.
4. Where necessary to complete octets, put in non-bonding electrons in pairs.

14. LEWIS STRUCTURES: STEPS
5. Check work by counting electrons in Lewis structure and comparing calculated number of valence electrons.

15. LEWIS STRUCTURES lO H–C–H CH2O V S C 4 4 H 1 1 O 6 2
12 8 / 2 = 4 bonds lO
H–C–H

16. LEWIS STRUCTURES
NH3
V S
N 5 3
H 1 1
8 6 / 2 = 3 bonds
H–N–H H

17. LEWIS STRUCTURES O–S–O O SO32– V S S 6 2 O 6 2 24 8 +2 -2
24 8
+2 -2
26 6 / 2 = 3 bonds
O–S–O O 2-