Bond Type
To calculate bond type
1. Look up the electronegativity of the atoms in question. (chart passed out)
2. Find the difference between the electronegativities. (subtract)
3. Use the chart to classify the bond as
nonpolar covalent (0.0 - 0.49)
polar covalent (0.5 – 1.9)
ionic (>2.0)
Determine the bond type of each of the following.
H2
H2O
NaCl
MgCl2
Covalent Bonding and Molecular Compounds
covalent bonding - bonding between atoms which results from electron sharing
The particle which results from covalent bonding is a molecule.
molecule - two or more atoms bonded covalently
There are eight elements in which two atoms bond forming a diatomic molecule. They do not
normally exist as single atoms. They are referred to as diatomic elements.
diatomic elements - two identical atoms bonded covalently
molecular compound - a chemical compound whose simplest formula units are molecules
Formulas Represent Compounds
chemical formula - a shorthand method of using atomic symbols and subscripts to represent the
composition of a substance
molecular formula - a formula indicating the composition of a molecule
dot formula - a formula using dot notation to indicate valence electrons
formula unit – represents the composition of an ionic compound, empirical formula
DIATOMIC ELEMENTS
NAME
DOT FORMULA MOLECULAR FORMULA
hydrogen
H2
nitrogen
N2
oxygen
O2
fluorine
F2
chlorine
Cl2
bromine
Br2
iodine
I2
astatine
At2
Lewis Structures
Lewis structures are formulas in which symbols represent nuclei and inner shell electrons and dots,
dashes, etc, represent valence electrons.
The Lewis structure of water would be similar to the dot formula.
Polyatomic Ions
A polyatomic ion consists of two or more atoms bonded covalently which has a net charge.
Show the Lewis structure for SO4=.
Show the Lewis structure for H2 SO4.
Examples
Show the Lewis structures for
MgBr2
Na2O
H3PO4
CH3Cl
Al2S3