chlorine dioxide carbon monoxidedinitrogen pentaoxide phosphorus pentachloride

silicon monocarbide sulfur hexafluoridedisulfur dichloride silicon tetrachloridesilicon dioxide chlorine trifluoridetetraphosphorus decaoxidesulfur dioxidedioxygen difluoridenitrogen trichloridediboron trioxidediarsenic trisulfide

chlorine monoxide oxygen difluorideberyllium oxide carbon tetrachloridephosphorus triiodide potassium permanganate

zinc oxide trisilicon tetranitridenitrogen dioxide phosphorus pentabromide

nitrogen dinitrogen monoxidetin(IV) cyanidedichlorine monoxidenitrogen trifluoridedichlorine octaoxidesulfur trioxide

TODAY: read page 37 and pages 164-167

Diatomic moleculesLewis Dot Diagrams for MoleculesHW: Worksheet – Lewis Structure

exercisesRetest: Monday Feb. 4Quiz: Thursday or Fri Feb. 7 or 8

ELECTRONEGATIVITYAND 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.

ELECTRONEGATIVITYAND 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

orBr2 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 STRUCTURESCH2O

V SC 4 4H 1 1H 1 1O 6 2

12 8 / 2 = 4 bonds

lOH–C–H

LEWIS STRUCTURESNH3

V SN 5 3H 1 1H 1 1H 1 1

8 6 / 2 = 3 bonds

H–N–H H

LEWIS STRUCTURESSO3

2– V S

S 6 2O 6 2O 6 2O 6 2

24 8+2 -226 6 / 2 = 3 bonds

O–S–O O

2-

POLYATOMIC IONSFROM NOW ON:know NO CO SO PO ions(–ates and –ites)know NH4

+

know –ides: cyanide, hydroxideknow chlorine containing ions