Covalent Bonding
by: Braelyn Gilman
Melting and Boiling Points of
Molecular and Ionic compounds
 Ionic
compounds are the strongest,
breaking the bonds takes immense
amounts of energy, boiling and melting
points extremely high. Ionic compounds do
not conduct electricity.
 Molecular compounds have no bonds to
break so the melting and boiling points are
low.
The Molecular Formula
 The
molecular formula specifies the actual
number of atoms of each element in a
molecule
 For example, the molecular formula for
water, H2O, specifies that there are two
hydrogen atoms and one oxygen atom
present in each molecule of water.
Result of Electrons Sharing in
Covalent Bonds
 It
helps an atom to contain a full shell part
of the time. They share ions to make the
shell complete and to make them happy.
 For
example if me and Tiffany each had
seven electrons but she lost one and I had
an extra I would share with her and it
would keep our shells to make us happy.
Electron dot structures and shared
electrons

Electron dot structure - valence electrons are
represented by dots placed around the chemical
symbol. Electrons are placed two on each side
of the elemental symbol for a maximum of eight,
which is the number of electrons in a filled S and
P shell.
 Period one (hydrogen and helium) represents an
exception where only a maximum of two
electrons are placed on one side of the element.
 Electron dot structures for the first two periods Number of valence electrons related to group
number
Atoms forming double or triple
covalent bonds





Covalent bonds: formed from sharing of two electrons.
Sharing electrons is one way that atoms can satisfy the
"Octet Rule" atoms, by sharing electrons to form an
electron-pair bond, can acquire a stable, noble-gas
structure". There are 3 kinds of covalent bonds based on
number of pairs of electrons shared between the two
atoms:
single covalent bond - 1 shared pair
double covalent bond - 2 shared pairs
triple covalent bond - 3 shared pairs
Bond energy: single < double < triple
Bond length: single < double < triple
The strength of a covalent bond
and bond dissociation energy
 They
are related by the energy needed to
break one molded bond.
 A large bond disassociation energy
corresponds to strong covalent bonds they
are unreactive partly because the
disassociation for each of these bonds are
high
Oxygen atoms bonded in ozone
 The
chemical formula for ozone is O3 three oxygen atoms.
 The ozone is created when oxygen
collides with atoms of oxygen producing
Oxygen
Some exceptions to the octet rule
 There
are two ways that atoms will not be
able to obey the octet rule. These are:
 1.
Having too few valence electrons to
ever obtain an octet.
2. Expanding the octet to have 10, 12 or
14 valence electrons instead of 8.
Atomic and molecular orbitals
relations
 A molecular
orbital is a mathematical
function describing the wave-like behavior
of an electron in a molecule.
Molecular orbitals are further divided
according to the types of atomic orbitals
The VSEPR theory helps predict
the shapes of molecules
 Valence
shell electron pair repulsion
(VSEPR) theory is a model in chemistry
used to predict the shape of individual
molecules based upon the extent of
electron-pair electrostatic repulsion.