Transcript Bonding
Bonding
By Mary Agarwala
Chemical Bonds?
What are they?
Why do atoms form them?
Why are some stronger than
others?
Ionic Bonding
+ charged ion is attracted to a – charged
ion
A nonmetal + a metal = ionic bond
Ionic compound is entirely made up of ions
Positively charged ion (Cation)
Negatively charged ion (Anion)
Ex. NaCl
Ionic properties
High melting points which
means it ionic bonds are strong
bond
Brittle
Dissolves in water, a process
that breaks the ionic bonds
and separates the ions (makes
solutions that conduct
electricity)
Polar…”Likes dissolves likes”
Liquid (motlen) ionic
compounds conduct electricity
Solid ionic compounds do not
conduct electricity well
OCTET RULE
Atoms tend to gain,
lose, or share
electrons in order to
acquire a full set of
valence electrons
Lewis Dot
Diagrams
Valence electrons are
represented as dots placed
around the element symbol
KNOW HOW TO WRITE IONIC
COMPOUNDS
Empirical formula vs.
Molecular formula
Empirical Formula
Denote the ratio of ions in a
compound
Chemical formula
Molecular Formula
Molecular compound
Describes the composition
of a molecular compound
The lowest possible whole
Tells how many atoms are in
The compound wants to be
Ex. Glucose (C6H12O6)
number subscripts for the
elements
electrically neutral
a single molecule of the
compound
Covalent Bonds
-A covalent bond is formed
by a shared pair of electrons
between two atoms
-Each atom wants to be
“octet happy”
-Nonmetal + nonmetal =
Covalent bond
-This is best shown by
combining atoms’ Lewis
structures
Multiple Bonds
Double Bonds
Triple Bonds
(show picture)
(show picture)
(text book pg 239. Eq.4)
(text book pg. 239 Eq.5)
Exceptions to the Octet
Rule
Atoms with less than an octet (BF3)
Atoms with more than an octet (SF4)
Molecules with an odd number of electrons
(NO)
Don’t sweat the exceptions for the regents
Electronegativity
Property of an element that indicates how
strongly an atom of that element attracts
electrons in a chemical bond
When one atom is SIGNIFICANTLY MORE EN
than another, the covalent bond is POLAR.
2 atoms, in a bond, with SIMILAR ENs are
NONPOLAR
KNOW EN TRENDS!!! Remember F is the
biggest (EN=4.0)
Bond Type by
Electronegativity
Electronegativity
Difference
Less than or
equal to 0.4
Between 0.4 and
2.0
Greater than or
equal to 2.0
Bond Type
Nonpolar
covalent
Polar covalent
ionic
Naming Chemical
Compounds
Chemists name a compound according to the
atoms and bonds that compose it
Write cation first
Naming Ionic
Compounds
No need to specify
number of atoms
(AKA no prefixes)
Ex. KI (potassium
iodide)
Ex. KNO3 (potassium
nitrate)
Ex. CuSO4 (copper(1)
oxide)
Naming
Molecular
Compounds
Know numerical
prefixes
Suffix –ide is added to
the atom with a
greater EN
Ex. NO2 (nitrogen
dioxide)
Ex. BF3 (boron
trifluoride)
Ex. P2O5
(diphosphorus
pentoxide)
THE END
“Good Luck.. Do Well!!!!”