1.
2.
3.
4.
How are the melting points and boiling
points different from ionic compounds?
What information does a molecular formula
provide?
How does electron sharing occur and are
represented in Lewis structures?
How do nonmetals react to satisfy the octet
rule?

What are key principles of Ionic Bonding?

Instead of a “tug-o-war” with electrons like
ionic bonding, covalent bonding shares!
 Ionic bonding- great difference in
electronegativity
 Electronegativity what?

Atoms held together by sharing electrons is
known as covalent bonding.
 A molecule: neutral group of atoms joined
together by covalent bonds

A diatomic molecule: molecule consisting of
two atoms (and only two).
 There are 7 naturally occurring diatomic elements!

Molecular compounds
tend to have lower
melting points and
boiling points than
ionic compounds.
 What does this say
about molecular
compounds?



The chemical formula of a molecular
compound
Shows how many of each element is
contained in a molecule
Does not tell you anything about its structure
Examples:
H2O, CO2, CO, O3
How are melting points and boiling points
different from ionic compounds?
 What information does a molecular formula
provide?
 What are the only elements that exist in nature
as uncombined atoms? What term is used to
describe these atoms?
 What term is used to describe two atoms
chemically combined by sharing electrons?
 How is the formula NO different from NO2?


In forming covalent bonds, electron sharing
usually occurs so that atoms attain the
electron configuration of noble gases.
Why do they share and not transfer?

Two atoms held together by sharing a pair of
electrons

An electron dot structure represents the
shared pair of electrons of the covalent bond
 A structural formula represents the covalent
bonds by dashes and shows the arrangement of
covalently bonded atoms
▪ Structural formulas also show unshared pairs!

Atoms form double and triple bonds if they
can attain a noble gas structure by sharing
two or three pairs of electrons
Draw electron dot structures of each molecule
chlorine, bromine, iodine, oxygen,
nitrogen
The following molecules have single covalent
bonds. Draw an electron dot structure for
each.
H2O2 and PCl3
1.
2.
3.
Count valence electrons
Draw all individual electron dot structures
Connect single electrons (bonds) until
everyone has an octet (exceptions are
hydrogen and boron)

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
SO2
SO3
N2O
HCN
HF
HCl



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



HCl
H2S
PF3
NH4+
NO2-1
SO4-2
NO2+1
C2H6
C2H2

Venn Diagram of comparing ionic bonding to
covalent bonding