Also called
molecular compounds
Covalent bond
- bond formed when two nonmetals share valence electrons to fulfill
the octet rule
- covalent bonds are weaker than ionic bonds (sugar/salt melting demo)
- low melting and boiling points
Covalent Bond Prefixes
1-mono
2– di
3-tri
4– tetra
5-penta
6– hexa
7– hepta
8– octa
9– nona
10-deca
Last element still
ends in –ide
PF5: Phosphorus PentaFluoride
XeF4:____________________
CCl4:____________________
SO3:_____________________
Dinitrogen Pentoxide: N2O5
Tetraphosphorus Decoxide: ________
Sulfur Hexafluoride: _______
Arsenic Trichloride: ___________
NAMING ACIDS-Always start with H
Ending of Anion
-ide
-ate
1. Add Hydro (prefix)
2. Replace –ide with –ic
3. Add acid
-ite
1. Replace –ite with –ous
2. Add acid
Do not add Hydro prefix
1. Replace –ate with –ic
2. Add acid
Do not add Hydro prefix
Example:
Example:
HCl ionizes H+ & ClCl- = Chloride
HNO2 ionizes into H+ & NO2NO2- = Nitrite
Nitrous Acid
Hydrochloric Acid
Example:
HC2H3O2 ionizes into H+ &
C2H3O2C2H3O2- = acetate
Acetic Acid
Drawing Lewis Structures
1. Calculate the total number of valence electrons in the compound. (# OF ELECTRONS
NEEDED)
2. Arrange the Atoms
- Carbon is ALWAYS central atom if present
- Hydrogen/halogens are always on the outside
-Central atom is often the 1st atom in the formula
3. Add one bonding pair between each of the connected atoms
4. Add the rest of the electrons until all have 8 (consider exceptions to octet rule)
5. When there are too many e- take away a pair from each adjacent atom and add a bond.
1 Bond (——) represents 2 shared electrons between atoms
single covalent bond
- a bond in which each atom shares one electron with the other (one pair of electrons)
- each atom needs one more valence electron
Cl2
+
H2O
or
+
double covalent bond
- a bond in which each atom shares two electrons with the other (two pairs of electrons)
- each atom needs two valence electrons
O2
+
+
or
CO2
triple covalent bond
- a bond in which each atom shares three electrons with the other (three pairs of electrons)
- each atom needs three valence electrons
+
N2
Nonmetals bond to have 8 valence electrons
(except hydrogen)
F2
O2
N2
F F
O O
N N
CO2
O C O
H2O2
H
O
NH3
H
O
H
N
H
H




valence electron shell pair repulsion theory
electron pairs repel each other and try to get as far apart as
possible
molecular shapes are determined by the repulsion of these electron pairs
Adding more atoms to a molecule adds more electron pairs thus
changing the shape of the molecule
Linear
2 atoms on central atom
No Lone pairs on central atom
180 degrees
Trigonal Pyramidal
3 atoms on central atom
1 lone pair
109.5 degrees
Trigonal Planar
3 atoms on central atom
No Lone pairs
120 degrees
Bent
2 atoms on central atom
1 Lone pair
109.5 degrees
Tetrahedral
4 bonds on central atom
No lone pairs
109.5 degrees