chlorine dioxide
carbon monoxide
dinitrogen pentaoxide
phosphorus pentachloride
silicon monocarbide
sulfur hexafluoride
disulfur dichloride
silicon tetrachloride
silicon dioxide
chlorine trifluoride
tetraphosphorus decaoxide
sulfur dioxide
dioxygen difluoride
nitrogen trichloride
diboron trioxide
diarsenic trisulfide
chlorine monoxide
beryllium oxide
phosphorus triiodide
zinc oxide
nitrogen dioxide
nitrogen
tin(IV) cyanide
dichlorine monoxide
nitrogen trifluoride
dichlorine octaoxide
sulfur trioxide
oxygen difluoride
carbon tetrachloride
potassium permanganate
trisilicon tetranitride
phosphorus pentabromide
dinitrogen monoxide
TODAY: read page 37 and pages 164167
Diatomic molecules
Lewis Dot Diagrams for Molecules
HW: Worksheet – Lewis Structure
exercises
Retest: Monday Feb. 4
Quiz: Thursday or Fri Feb. 7 or 8
ELECTRONEGATIVITY
AND POLARITY
• electronegativity = ability of an atom to
attract electrons in a covalent bond
• most electroneg. element = flourine
• least electroneg. element = francium
• Unequal sharing of electrons will produce
a polar bond.
ELECTRONEGATIVITY
AND POLARITY
•
•
•
•
F–F
H–F
H2O
NH3

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
show the valence electrons as
dots
 inner electrons and atomic nuclei
are represented by the symbol

group 1A: 1 valence e group 2A: 2 valence e-, etc.


diatomic molecules
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)
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.
5. Check work by counting electrons in
Lewis structure and comparing
calculated number of valence
electrons.
LEWIS STRUCTURES
CH2O
C
H
H
O
V
4
1
1
6
12
lO
S
4
H–C–H
1
1
2
8 / 2 = 4 bonds
LEWIS STRUCTURES
NH3
N
H
H
H
V
5
1
1
1
8
S
H–N–H
3
H
1
1
1
6 / 2 = 3 bonds
LEWIS STRUCTURES
SO32–
S
O
O
O
V
6
6
6
6
24
+2
26
S
2
2O–S–O
2
2
O
2
8
-2
6 / 2 = 3 bonds
POLYATOMIC IONS
FROM NOW ON:
know NO CO SO PO ions
(–ates and –ites)
know NH4+
know –ides: cyanide, hydroxide
know chlorine containing ions