COVALENT BONDING
What is a Covalent Bond?
The chemical bond that results from the sharing of electrons
Non-metals combine to acquire a full valence shell of 8 valence electrons
What types of Covalent bonds are there?
Single Covalent bonds- (also called sigma bonds) When a single pair of electrons is shared
Example: H
H
Group 7A: will form single covalent bonds
Group 6A: will form two single covalent bonds Ex: H2O
Group 5A: will form three single covalent bonds Ex: NH3- Ammonia
Group 4A: will form four single covalent bonds Ex: CH4- methane
Multiple covalent bonds: Double or Triple bonds
Double covalent bond- when two pairs of electrons are shared.
Example: O2 (draw lewis structure)
Triple covalent bond- formed when three pairs of electrons are shared between two atoms.
Example: N2
shares three pairs of electrons.
Pi bonds π- multiple bond consists of one sigma and one pi bond.
triple bond- one sigma and two pi bonds.
The shorter the bond the stronger the bond. Triple bonds are shorter.
Which atoms are diatomic molecules?
H2
O2
Br2
F2
I2
N2
Cl2
NAMING COVALENT COMPOUNDS
Covalent means both Elements are non-metal
A prefix is added to the name of the first element in the formula ONLY if more than one atom of it is present.
A prefix is ALWAYS added to the name of the second element in the formula
The second element will use the form of its name ending in ‘ide’.
PREFIXES
MONO
1
HEXA
6
DI
2
HEPTA
7
TRI
3
OCTA
8
TETRA
4
NONA
9
PENTA
5
DECA
10
When a prefix ending in ‘o’ or ‘a’ is added to ‘oxide’, the final vowel in the prefix is dropped.
MONO is NEVER used on the first element even if one atom is present
Second element should ALWAYS have a PREFIX and end in -ide
EXAMPLES:
FORMULA
N2S4
XeF6
P2O5
NAME
Dinitrogen
Sulfide
Xenon
Hexafluoride
Diphosphorus
Pentoxide
WRITING FORMULAS
Once again, use the prefixes to determine the subscript
EXAMPLES:
NAME
NO2
SF6
XeF4
FORMULA
Nitrogen
Dioxide
Sulfur
Hexafluoride
Xenon
Tetrafluoride
PRACTICE ASSIGNMENT: COPY IT FROM BOARD
FORMULA
NI3
CCl4
SO3
NAME
Nitrogen
Trioxide
Carbon
Tetrachloride
Sulfur
Trioxide