Add up all valence electrons in the molecule
Lewis dot structure rule 1
Place the least electronegative atom in the center. H never goes in the middle; oxygen rarely; carbon almost always
L.D.S. Rule 2
Place the remaining atoms symmetrically around the center
L.D.S. Rule 3
Use lines to connect atoms
LDS rule 4
Place dots around the atoms until they add up to the total valence electrons. Bonds account for 2 electrons.
LDS rule 5
:Ö = C = Ö:
CO2 Lewis dot structure
H
|
H-N-H
|
H
|
H-N-H
|
H
NH4^+
Cation + Anion (metal + nonmetal); anion ending changes to -ide
Ionic bonds
Ba3N2
Bond Ba^2+ and N^3-
Fe(III)F
Fe^3+ F^1-
FeF3
Fe^3+ F^1-
FeF3
Transition metals will be given a charge in Roman numerals. If not specified, charge is +1
Cu^+4 O^2-
4
CuO2
4
CuO2
Cu(IV)O
Cadmium (II) oxide
CdO
Sharing electrons between 2 nonmetals
Covalent bonds
Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
Prefixes: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Ionic: is the metal main group or transition?
Trans: Roman numerals
Covalent: covalent prefixes
Trans: Roman numerals
Covalent: covalent prefixes
Is it ionic or covalent?
H2 O2 F2 I2 N2 Br2 Cl2
Diatomic elements
MnO4^-
Permanganate
CO3^2-
Carbonate
CrO4^2-
Chromate
Cr2O7^2-
Dichromate
O2^2-
Peroxide
HPO4^2-
Hydrogen phosphate
SO3^2-
Sulfite
SO4^2-
Sulfate
PO3^3-
Phosphite
PO4^3-
Phosphate
NH3
Ammonia
NH4^+
Ammonium
H3O^3
Hydronium
C2H3O2^-
Acetate
CN^-
Cyanide
OH^-
Hydroxide
ClO^-
Hypochlorite
ClO2^-
Chlorite
ClO3^-
Chlorate
ClO4^-
Perchlorate
NO2^-
Nitrite
NO3^-
Nitrate
